In my experience this is less and less the case. I think it's largely a function of developer effort. In fact, at this point I consider a number of apps (WhatsApp, Wechat, Zalo, Viber, Twitter, all of Google's apps) to be more usable in their Android incarnations than they are on iOS. This is partly to do with the greater degree of platform integration Android allows and, I suspect, the fact that it's just harder to introduce crash bugs in Java than Obj-C. Text entry on Android is currently vastly superior thanks to Google's very good stock keyboard and the plethora of excellent third party keyboards.

iOS is clearly ahead when it comes to anything having to do with multimedia but for a very large class of apps these days it's either a tossup or a win to Android. iOS 8 will probably close the gap to some degree because it allows devs to hook into the OS to a degree that was never possible before but I also expect Android apps to improve now that people can afford to ignore 2.x and the baseline for cheap phones has been raised by the Android One program.