It has been about a month since I upgraded my Asus Transformer TF300 Android tablet from Jelly Bean 4.1 to 4.2.1. The upgrade was relatively painless although it is quite a large download.
The main differences are that you can change the GUI from the traditional tablet layout to the newer, phone I guess, layout. This puts the notifications, clock, etc. on a smaller, upper task bar. The soft buttons for back, home and task manager stay at the bottom and keep their original size.
The layout is similar to the Linux Gnome layout – which I know quite well, being a Linux fan. I am also a BlackBerry Playbook fan! Other than the fact that at the launch the number of apps, well, sucked, and frankly while getting better still has quite a way to go – I think that the interface and underlying QNX OS is really well done. In fact, one of the biggest surprises I had with the new Jelly Bean 4.2 GUI was that the upper tool bar menus are accessed by a downward swipe! Very similar to the Playbook but without the touch sensitive bezel. (And the speakers on the Playbook are great – the TF300, not so much…)
That being said, upgrading from the traditional tablet layout to the newer layout means that all your grouped apps disappear and you have to go about setting things up again. No settings seem to be lost but still is is a pain in the ass.
There is a new multi-user capability which means everyone can have their own login. However, the segregations is NOT as good as one would expect on a full-fledge OS. It is not there yet but is something that I think will get better over time.
Given the cost of most tablets (ahem… Apple – and yes I had an iPad first gen until I gave it to my wife) they are not what one would consider affordable as a single user device – unless you are part of the 1% club….