I'm seeing the same type of stuff on my 920. It ran fine for a couple of weeks, now it's very laggy, apps close spontaneously, keyboard won't come up, Edge is crazy slow, BT drops or won't connect and calls using BT are staticky to the point that you can't understand what's being said. And I'm very tired of doing hard resets.
Two of my coworker friends have been diehard WP supporters like me since the 7.0 days (we all bought Samsung Focuses!), but they've both switched to iPhones in the past 2 weeks. I won't give my money to Apple, but I'm sorry to say I'm starting to look at android. I'm flabbergasted that MS has screwed up their mobile business so badly. I've been directly responsible for bringing at least 8 friends and family to WP over the years, but now I'm starting to feel embarrassed about it.