- About every day (sometimes much more frequently) a tab will just die. You'll click a link or enter a url, and the indicator in the top left corner will start spinning, but nothing ever happens. The only way to fix it is to close the tab and open a new one.
- Less frequently - maybe every few weeks or less - large blocks of web pages will just not render, instead of text or graphics or whatever should be there, there are just giant square white chunks. The only way to fix this is completely reboot the iPad.
I've also had a number of weird problems with the iTunes app that have required finding a way to force the app to quit or reboot the device to fix.
I like my iPad, but Apple's stock apps have quite a bit of room for improvement.
Have they ever used the Facebook client before the ObjC rewrite? My girlfriend had to learn both force-killing and pull-to-refresh because of all the bugs (on an iPad if that makes a difference).
I cannot speak for Android, not being a regular user, but I have never, ever seen a first-party on iOS get its own UI stuck. It may crash rarely, but it will never get itself into a state where the user is powerless to do anything with it (short of killing it).
Most iOS users I've met aren't aware of the kill-app functionality, and they don't need to, because first-party apps don't have egregious enough bugs like "button to return to main menu reacts but does nothing".