From the apps I use:
Major apps like Pocket, Evernote and Flipboard are equally good on Android.
Less widely used apps tend to look less polished on Android, but some have better functionality there. My Data Manager is the best data manager I've found - on iOS this doesn't let me track the data used by individual apps, but on Android it does. The Android version is also more reliable when it comes to staying in sync with my actual data plan.
Generally I get more out of the Android versions of many apps because of how freely you can share to/from them. Comparing iOS/Android versions without taking the general functionality of the OS itself into account is often quite pointless. Android also has swipe typing - for me that makes any and every writing app superior on Android, no matter how slick the best writing apps look on the iPhone. The fact that there are Android phones with larger screens can't really be overlooked either, which is why I also prefer any office type app, reader, or streaming/video app on Android. (Obviously this might change with the iPhone 6.)
Many apps are of course lacking on Android, notably many games titles, and basically all good multitrack music recording apps, if you're into such things. This is one of the main reasons why I still keep my iPhone 4S around (for the FourTrack app).
Android on the other hand has some apps that iOS doesn't. Google Keep for example is one of my most loved apps and the best note taking app I know that syncs well with in-browser editing. This is even my go-to app for longer writing, because of how simple it is. (Actually the Notes app on iOS 7 is impressively ugly, I still can't understand how Jony Ive let that one slide
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So, I didn't structure this post very well but you get the general gist: you have to take the whole of the experience into account when comparing app quality on these two platforms, IMO. So far I think devs in general have spent more time polishing iOS apps because that's where the big money has been. That is clearly changing though, and as others have said, app quality on Android is improving by the day. Many things that irked me when I got my Note 2 one year ago have since been dealt with and the whole Android experience has improved remarkably in just one year.
Lastly a word of advice, from experience - it may be that you don't like how Android is on just one particular phone. For instance the experience with TouchWiz on the Samsung phones can be very different from the stock Android on a Nexus 5. If you really want to give Android a chance, you won't make up your mind after testing just one phone
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