I grabbed one of the first units back in August.. its as impressive as stated on the package... however the initial units were quite buggy and crashed randomly and quite often... this was largely due to the lack of free RAM available for applications running on the phone.
However, SE, as per usual have stuck to it and released a couple of firmware upgrades (via the SE website) which have improved the usability of the phone quite a bit. It hardly crashes now and is an excellent piece of kit. I'm sure SE will release a couple more firmware updates in the next couple of months to smooth out any of the remaining problems i.e. if you have a load of apps open.. and decide to open another one.. it'll kill off one/some of the already running apps - this can be quite annoying, however I've learnt to kill apps as i finish using them now... aids battery life too...
All in all, I wouldn't have any other phone (I am a little biased however... have been dedicated to SE's P series since the P800 first hit the stores in October '03).
MdSalih
P.S. Like you guys... I also picked up a K800i in anticipation of the P990 in early August - another solid phone by SE
