I did the manual install on release day and had problems, mostly with battery life. Since then I installed the updates and did a lot of tweaking and it's running like a dream now. On the other hand, my wife only installed the ICS update (identical E4GT, bought at the same time as mine) 3 days ago and didn't have a single problem. We've both installed Go Launcher too and are getting great battery life and performance now.
I had severe issues with FH18 the first roll out....Sprint store downgraded my ph back to GB....but still had problems......Sprint ordered another ph for me which was a refurbished one.....but it already came loaded with ICS....phone had no problems so I downloaded FH13 via Samsung Kies.....I have no problems what so ever now with FH13.....Only way you're gonna know is to download it.....as suggested after downloading and installing FH13 reset the phone and you'll be fine.....for me and others using Go Launcher made battery life worse.....Just my 2 cents!
FH13 is pretty good. Although, like carole, I haven't really had issues with any of the ICS builds. FI03 is awesome imo, but it's only available as a leak atm, not an official OTA.