I switched to the Nexus, still not sure if it is a temporary switch, depends what the next iPhone brings, but at the moment i'm not really missing anything specific about iOS.
I should note a few things though. First of all, I don't suffer from OCD-like symptoms like some people on here... sure, I like to set my radio volume to an even number (even better if it rounds off to the nearest 5 without being too loud or quiet) but when it comes to my phone I don't baby it, I dont spend the last 15 minutes of my day checking for a new scratch to get annoyed about, I dont put a case on it, and I can handle flaws providing usability doesn't suffer. I'm also not a mobile gamer. I have a PC and consoles for that. I have never needed to "game on the go". I drive to work, when I'm at work I work, and when I'm not at work I'm either at home or out with people, so I would never break my phone out and be unsociable and start gaming on it.
So, with that in mind, the Galaxy Nexus...
At first I was unsure about the size. I tried visiting a bunch of stores to get my hands on one before I pulled the trigger but no where had it in stock. It's all about the S3 and One X in stores now. I ordered one anyway. My iPhone 4 home button had died I wanted to try out android again after giving the S2 a brief go. I couldn't see past the low res screen on that device. I also wanted to have a raw Google device. No custom launcher, no waiting for updates, just a bog standard Google phone.
First thing I noticed upon arrival is that the size wasn't too much of an issue at all. Weight is slightly less than the iPhone and it's well balanced, felt great in my hand. Build quality is great (even though people like to complain about "plastic phones" since Apple doesn't use a plastic back anymore). No bad edges, something that always bothered me about the iPhone 4, and so few physical buttons. It's so clean and stylish to look at, but that's just personal taste I guess. The glass also looks amazing, the way the edges are smoothed round in to the bezel, beautiful. It gives the front a sort of pebble look, similar to the old HP WebOS phones (wow... I cant even remember their names off the top of my head now).
Display. First of all, to the naked eye, it is as sharp as the iPhone, no doubt about it. You aren't going to switch and think "damn this dpi is low", but it has it's pro's and cons. The pro is that colours are just much nicer. The iPhone feels so washed out in comparison. It's much more vivid and matches up more with any decent quality monitor. The con is the pentile tech; at low brightness settings you are going to notice "grains". That's the only way I can describe it. It just looks slightly grainy. The only thing that makes this ok is that it's not all that noticeable in many situations. You probably wont notice it on your home screen unless you have a very plain background, ie single light colour, no objects, and most other uses on your phone probably wont show it either, websites, and especial photos and videos are not going to show it. Forums and some apps are when it is most noticeable for me, but personally, I don't really care all that much, others do. You could counter this by upping the brightness, but this will hurt battery life and probably your eyes in low light situations. I rely purely on auto brightness. In a well lit room it is much less noticeable when the brightness is higher to compensate for the lighting.
Speaking of battery life, another con. This phone just doesn't last as long as an iPhone on a single charge without messing around, and i'm not really in to that any more. I used to jail break, I went as far as rooting this phone to get Jelly Bean early, but other than that I dont really want to be messing about. I downloaded an app called juicedefender, it helps with battery life but it's still not quite as great as the iPhone. I guess this is just a problem with having a large display. So far it has not failed me throughout a day, but I am closer to zero than I was on the iPhone. This, again, is going depend on you as a user and what you do with the phone, and how much you do. I'm probably not as heavy as most people. I check a few websites, use a few news reader apps, email, facebook, twitter, instagram, a low amount of calls and some texting.
Apps. a lot is mentioned on here and other sites about apps. I'm not sure everyone has the full picture before commenting. Personally I find there isn't a single app that I used regularly that isn't available on the Play Store, or has a free yet equally functional alternative available. People like to talk about the low quality of android apps but I have not found this to be the case. As I mentioned above, I am not a mobile gamer. It is entirely possible that a game you like won't be available on the Play Store, I know iOS gets "exclusives" but this isn't something I care about. Though I will say that some games that have a cost on the App Store are free on the Play Store. I noticed all the Angry Birds and a few Gameloft titles were free. Possibly add supported? I can't comment, something to check if thats what you're in to.
Widgets. Not massively important to me, but still kind of useful to have. I have a weather/clock widget on my home page, great for the obvious, as well as quick access to alarms. I have a calendar widget on another screen for a quick swipe and reference of any upcoming events and reminders. Swipe the other way from my home screen and I have a small data counter so I can keep an eye on my allowance while I'm still in that playing-around phase with a new phone.
OS/UI. Personally I really like it. I like that this OS has an "app draw". No need to hide stuff away in a folder or your last home screen screen and pretend it isn't there, just remove it from your home screens completely and forget about it. there are apps that I even access solely through this because i don't use them very often. Another great feature of Jelly Bean is Google Now. What an amazing feature they have added. I use this every morning before my commute, and again before I leave work, to get everything I need to know on a single screen... weather, traffic updates, and reminders. It's a very useful tool and I'm hardly using any of the "cards" yet. As far as smoothness goes, it's smooth. No problems with stuttering or lag. It's another thing people make a big deal about but personally I never noticed an issue with this even on the S2. It seems to me that the hardware was already doing enough to battle it, even before Jelly Bean came a long and really finished it off. Flicking between homepages and scrolling through apps feels no different to iOS.
Buttons. As I mentioned, few physical buttons. Power and volume on the sides, that's it. Positioning of the power button is perfect for left or right handed use, within reach of my thumb or index finger depending on which hand it is held in. I thought I would find the software keys difficult to get used to and would maybe catch them by accident while typing but this hasn't been the case, and they are very responsive like the rest of the OS. The dedicated back button is amazing, by the way. Here's an example, you receive an email with a webpage link. Click the link and it will bring up your browser and open that link in a new tab, you can then go off browsing more pages from that page it you wanted, but click back (either once, or as many times as needed if you have gone off clicking other links) and it will close that tab, quit the browser, and take you straight back to the email. Not so useful if you have clicked through a bunch of links, you're probably better clicking the dedicated multitasking soft key in that situation, but if you haven't gone off through many pages it is a great way of closing that tab and returning to your email. This applies to many other apps. You might be in a news app that links to a youtube video which brings up the youtube app. Again, click back when you are done and it will kill youtube and take you back to the app that linked you. This is one amazing and smooth feature after putting up with that clunky iPhone home button for closing apps or multitasking.
Camera. This is a bit like the screen for me in that it's hard to decide if it is better of worse. Personally I think the overall quality is slightly lower than the iPhone 4 camera. At first I was disappointed by this, I mean, this phone is a year younger than the iPhone 4. After using it more I have found it has balanced itself out though. It has a great focus, even when up close to something. I always found the iPhone struggled with this. It also has a better focus for getting a sense of depth so although the quality might be a little less, it can produce some nicer photos, if you get me.
All in all I'm enjoying the phone. The size difference was easy to get used to, the OS is nice, smooth, and refreshing to use. I've had it for a few weeks now and never felt that itch to put my sim back in my iPhone. I think I still stand by what I've said to people in the past, and that is that my ideal phone would be a combination of an Android device and an iPhone (software and hardware), but individually I'd be hard pressed to take one over the other, so I guess that's a pretty good position to be in.
Previous smartphones have been the iPhone 3G, 3GS and iPhone 4. Take this review however you want, but the OP asked if anyone has tried one... I have (and still am), these are my views and opinion of the phone.
If you have any questions about it feel free to ask, but I'm not here to take part in the Android vs iPhone epenis comparisons.
