2.2.1 is DEFINITELY worth the upgrade, I wasn't going to bother at first but after I did the difference is just ridiculous! There's no lag whatsoever, my quadrant score went from about 900 to about 1500, and the biggest annoyance for me, media scanner, now takes less than 1 minute to scan my entire 16gb sd card instead of about ten minutes like it used too.
I know using Odin can be daunting if you have never tried before but there's plenty of guides on how to do it, and plenty of people here who can answer questions you may have before doing it, trust me you will NOT be disappointed.