for smartphones its hard to determine or measure how long the battery will lasts because it depends on how the user use the phone. i can say my milestone can last for 3-4 days if i use it as a phone, but it will only last for 5 hours if use hsdpa and heavy browsing. telco signal strength also affect the battery consumption, the lower the signal, more battery juice will be used to get the signal.

amin_bp:

1. never tested exchange, my company didn't provide the feature.
2. i dont use the keyboard that much, so far its working fine. but there are cases with the keyboard backlight not working. i think u need to play with the actual thing for few minutes (typing email, sms, notes etc) and see if it fits u. milestone keyboard received a lot of complaints mainly because of the design. buttons are a bit small (to make way for the d-pad) and they are not raised like other good keyboards. u may not be able to type fast (because u cannot feel and remember the buttons placement) but it gets the job done.
3. milestone has only 256mb ram, so if u put a lot of widgets on the home screen or have many apps running in the background, it will surely lag. but so far for me it is acceptable, not reaching the 'annoying' level of lag yet. but there are other phones out there having 512mb or more ram and still lags.
4. hardware quality is excellent. motorola really like metal stuff. that is why most motorola phones are heavy. do not drop it and it will last or protect it with some casing. i dont know about brightstar. i myself using starhub set. there are issues with software, alarm bug, music auto playing but i think it will be resolved in the next update. u can fix it now by flashing some files though. i've experienced a reboot once, that was during the phone running at 1GHz and i was tethering using hsdpa connection. the phone got too hot and it reboot itself. if im not mistaken, the design of milestone put most of the chips at one place near the camera. the phone will get hot when we use 3g/hsdpa connection or overclock it.

actually the signal issue on iphone4 is quite exaggerated. there are ppl who has no problem using it.