Okay, I installed it.. Had issues with the Samsung Keyboard FC'ing, I had more progress switching to Swype. Managed to get Titanium Backup to notice my licence file (put a copy on both the int and ext sd), but I couldn't get any of my apps to restore. It just froze, I tried switching the location that it restores to, but it just didn't work. The ROM itself seemed pretty good, better than I was expecting, but I can't really run it as a daily until I can get all my apps installed (and I'm not doing them manually!)
For a start you'll probably find them cheaper on eBay.. they do work, usually by entering a code on the handset. They are very small and flimsy which means they can be fairly delicate and stop working, but also you may have trouble getting the back of your phone on as they aren't THAT slim.
Yes it's based on a new ROM from Samsung which is Version 2.3.5 instead of 2.3.4, Samsung don't release changelogs between versions, so you have to find the differences yourself, there is a slightly altered font and apparently mildly better battery life in this latest update (probably some bug fixes too!)