i've been using my nokia e71 for a week and a half now and there are quite a few things that i like, and quite a few that i don't.
one of the first things i did when i got it (after buying an 8gb micro-sd card for it) was pair it with my imac over bluetooth, then run isync and push my calendars and contacts to it wirelessly. the ironic part, of course, is that isync is made by apple and comes with mac os x, but it doesn't work with apple's own iphone. it does, however, work with pretty much every other non-apple phone i've ever had.
over a year ago, i switched from a blackberry curve to the apple iphone. the iphone has been a fairly good smartphone and i haven't had too many complaints, until a month or two ago when everything on it started to get really slow and laggy. opening an application like notes or sms would take a few seconds to show anything, then another 5 or so seconds to actually respond to a tap. by the time the camera application would actually show its video, whatever i wanted to take a picture of had usually changed or moved.
the lack of 3rd party apps quickly led me to jailbreak it so i could run things like mobileterminal with openssh and vnc. while neat at first, jailbreaking quickly became a pain in the ass, usually leaving me a version behind the current release for a while until a stable jailbreak had been released. i resisted upgrading to the 2.0 firmware for a long time partly because it hadn't been jailbroken, and the app store apps were pretty lame compared to what i already had installed.