For as long as I can remember I have had some sort of Apple product, whether that be iPod, or MacBook or iPhone. Then I discovered the Galaxy Note 4. I didn't want to admit it, but I thought "Wow, this is really better than iOS". I also started to realize how much I hated the ugly bezels on iPhone and iOS 7 was simply unusable, the user experience no longer was better on iOS.
Then, another thing happened. I went to Best Buy and triied the Galaxy Tab/NotePRO lineup. And I've wanted the NotePRO 12.2 ever since, and now I'm going to try selling my iPad to attempt to get it. I've also recently started learning various programming languages so the ability to actually code for a mobile OS without buying an overpriced and walled Mac is awesome.
But my main reasons for switching to Android:
Customizability. Just changing backgrounds and app orientation isn't good enough for me.
Open Source. If I'm going to build apps, I want to be able to use any computer I want, not a specialized one.
Features. Features such as widgets (in how I feel is the right way), larger screens, custom launchers/keyboards/ROMs and removable batteries are going to really help improve my smartphone and tablet experience.
Fragmentation. iOS is simply unusable now because of fragmentation. Apple turned an amazing product into their own "toxic hellstew" Android is really just "free will" at this point. Even if my phone doesn't get the newest software, I have the choice to slap on a new launcher, theme and/or keyboard and call it a "software update".
Standard Connectors. This is technically a feature, but it deserves a bullet point of its own. By using microUSB, I can almost guarantee that I'll be able to use my current cords for at least 10 years with pretty much any other phone, casual camera, hard drive, computer, flash drive or portable battery. This is amazing, and I can't believe Apple hasn't changed their charger standard yet.
I figure that I might as well give my opinions on all mobile platforms for a negligible reason that may or may not actually add to the value of this post.
iOS:
iOS is still what I'd recommend for kids and old people. It's a simple user experience with really no good value. The design, while basically being a grid, is minimalistic, secure, easy-to-use and plain. This is sufficient for many people, I just happen to not be in that group.
Android:
Android is a great OS, but it can be complicated for some non-tech-savvy users, which is what I see with a lot of Apple users. I'd recommend it to anyone who wants something more than iOS, and/or someone with a more artistic flair and a need for customizability. And with Android Lollipop, I don't think there's ever a reason to go back.