Hey people, glad to see some responses, hope me bringing it to your attention helped.

I haven't actually installed the firmware myself yet, despite JB having been so buggy for me because I've never flashed Roms or anything so wouldn't know how to fix it like some of you would if it made things worse somehow. The reason is I was worried they might have brought back the fully-charged battery beep/vibrate that this phone had when running Gingerbread. This didn't bother most people but I'm a light sleeper and charged my phone at night by my bedside!
I don't have any reason to believe that they have brought back the buzz/beep, especially as it's not some big OS change like JB was, I'm just being VERY cautious because before the JB update fixed it I was thinking of selling the phone purely because of the un-turnoffable beep/vibrate!
Could anybody who has installed the firmware be so kind as to fully charge their phone and see if there's an annoying buzz/beep?

(Or obviously say if you notice any other bad things about the update).