For me personally, this was a terrible update. The phone no longer goes into deep sleep when it's not being used, meaning it used 3-4% battery an hour when idle. There's a tonne of people experiencing this problem on XDA forums. It all comes down to wakelocks, I fiddled endlessly to resolve it but no luck.
The upside of this for me was that it effectively forced me to give the finger to Samsung flavoured official ics, and I've since gone back to GB, full wipe/factory reset, and now I'm rocking CM9. Uuurgh, it is so so SO good, can't believe I've not done it earlier. It's like a new phone, I'll never go back now.
I followed this simple guide;
How to install custom ROM - For beginners - xda-developers