there. The FB app is incredibly bloated, memory heavy and does all kinds of crap in the background, even when your phone is trying to sleep and you haven't even opened the app. Make sure you're checking the battery usage stats regularly to see what's eating all the cycles while it's in your pocket. You might be surprised. In most cases, it's installed apps that are making your phone sluggish and unpleasant to use. In answer to your 2nd question, yes, I would expect a factory reset to do a lot to get that snappy feel back.