I have now had the Sprint Upstage by Samsung for a year and here are the complaints I have:

1) The phone is skinny, which is a plus in your back pocket, but not so great on you when you are holding the phone between your ear & shoulder b/c your bluetooth died. Or if you are like most women and carry the large purses, it will get lost.
2) If the phone is on vibrate or any other silent setting it will NOT warn you if your battery is low. It will just die to the point it must be recharged before it can be used again.
3) There is no blinking light, like on most phones, to let you know if you have a new vmail or text. You always have to unlock it and check.
4) If you are using the interenet/calendar/text/contacts, basically any feature that requires you to enter information into the phone, you have to constantly flip the phone over b/c you can only text on one side.
5) The texting/calling screen is small compared to phones of similar size.
6) Lastly, Just like the other individual who wrote in, my phone has crapped out twice w/o warning and I have had to reset it.