Have now managed to upgrade to JB. All very easy. I did a fairly ruthless pruning of apps which I'd been meaning to do for some time. I took out the SIM card and the SD card as a precaution then did a backup via Kies. I ran the update and all ran smoothly. When I turned it back on all was pretty much as before so I didn't run a Kies restore. Is there any reason to do this? The only thing I have noticed is that all my S Memos have disappeared. I thought that they might show up in S Notes but they haven't. I'm not that worried as there weren't many and I wrote them all out manually before I updated.
As to my first impressions, I had a quick look at vanilla Touchwiz but I'd never previously used it so switched to my usual launcher, Apex. I'm a bit underwhelmed so far, I have to say. I had heard all about Project Butter and how it should make swiping between screens smoother etc but I haven't noticed any difference. The dual-tasking is a clever function which I can see me using occasionally. I am really hoping that it will make a difference to the battery life as it has improved since I bought the battery mentioned in another thread but could still do with lasting a little longer. Are there any other additions with JB I have missed?
I'm wondering whether a factory reset is worth it. It partly appeals to start again from scratch but it's a bit of a hassle and I'm not sure whether it would be worth the grief. Any thoughts anyone please?