Just got my new i8910 - debranded and unlocked it (had to install XP on a spare HDD!)
Happy with it so far - only been 2 days, bit of an expensive route to get here, bought the N97 (too many issues) and before that the i8510 (though I had it for 8 months) hopefully will have this one for a while!
One question though does anyone have any suggestions for settings to help extend the battery life as I see some people are complaining about it.
First and foremost, wait two weeks. After that the battery will be fine. Secondly, update your firmware to the latest version. Thirdly, the usual stuff like keep bluetooth off when you don't use it etc.
But basically, when you use it as a phone, it'll last you 3 to 4 days. If you play unconverted xvids or surf the web a lot, using a bluetooth keyboard whilst habing wireless IRC run in the background, the battery will be flat in hours. Of course, there are other ways of torture that work.
MY experience is that it's better then any of the many N-series and older smartphones I had, and better then the I8510. That one also had a TERRIBLE battery life the first few weeks, but usually (tho not always) turned out OK.