Right now I prefer iOS but I must say I am impressed by the Nexus 4 of my girlfriend. I had an Samsung Galaxy S3 but switched back to iPhone about 2 weeks ago.
Altho i do like Android a lot, I prefer iOS in the end. It all comes down to day to day use.
1. Widgets are cool, but in the end pretty useless for me:
I want widgets for my mail, spotify, facebook, ... things like that.
* The mail widget is useless. Either you put it on fetch and you have your new emails in your widget but you lose lots of battery and date or you let your widget search the emails by 'tapping' it. But the widget itself has too little options to really be usefull. So I end up opening the email app anyway.
* Same thing with the Facebook app. I can "Tap to Post" on my iPhone quicker then I would make a post on my S3. Furthermore, the widget on my S3 did not update correctly like it should've. The posts "got stuck" in time.
* The Spotify widget worked fine but did not show up on the lock screen. So whats the point anyway. iOS music controls take over the app, which is way more usefull.
* A quick widget for weather is build in, in iOS also. The weather widget on my S3 used a lot of battery and made the phone stutter.
* It's a pain to find decent looking widgets that are somewhat comparable to eachother. The all look different and it's difficult to make your homescreens look somewhat attractive. I ended up removing them all. They were ugly.
* Calendar widget is very useful tho!
* Camera access on the lock screen on my iPhone is super handy.
2. Quick toggles are very handy but will be in iOS 7, so nothing lost there.
3. Animations are and speed is more consistent on iOS
* Android can be slow sometimes. My S3 was a quadcore phone but apparently moving through the homescreens while widgets were installed, made the phone lag. Which is pretty upsettings considering the price. Facebook Chatheads are super handy but made my phone run out of RAM
So I switched them off.
4. I hate touch buttons but apparently nobody agrees with me since it's a trend
At least Samsung still gives us one real button below the screen. You can take pictures with the iPhone with the volume button, which is again super handy.
But...
5. It's easier to share stuff on Android. It's annoying to be in your photo gallery on your iPhone and not being able to share your photo directly to someone on Whatsapp. This is still the most hated thing for me of iOS. Can't I just freaking get some stuff on/off an SD card? Can't I just download and open something in another app? It's all a bit too app centric. It's not that bad on an iPhone, but on the iPad, you want to be able to do more stuff and Apple complicates things.
Overall, I think iOS is more useful.