Maybe in your experience but not in mine. I've found Android apps equally as good. And from what I can remember, pretty sure I prefer Twitter on Android.
Since you mention Twitter, I think that’s where the true difference comes in. Twitter is a major app, and I’d guess has a good app development team in place. In my recent experience, those apps are in good shape. But where the difference is more apparent is that next tier of apps. I was very surprised by how buggy the Yahoo Fantasy app was on Android, and other apps, like my local news app, even the official Green Bay Packers app had too many minor annoyances that you simply don’t see on iOS. I will say that the difference isn’t quite as bad as it used to be, but it’s still definitely present.