I had my Indulge for about 6 months and really regret the service, especially my experiences with MetroPCS. I would _NOT_ ever recommend this phone or MetroPCS to anybody other than my worst enemy.
When the phone works - it's great. I was amazed that it could even receive GPS within my house (a weak signal from a satellite over 12,000 miles away).
But it never worked that well. The only reason I stuck with it was that I had spent a bunch of money to purchase the phone and since it would only work with MetroPCS I was stuck - if I decided to go with another company then I would be out the price of the phone.
In terms of hardware -
The GPS receiver went down many many times. There's a thread on the GPS problems here which I've contributed to. About half of the time the soft reset procedure for the GPS worked. But the other times I had to back up my phone, do a hard reset, and then restore the phone from the backup - a process which takes a couple of hours. In addition some of the desktop settings are not backed up so I had to tweak them each time.
The voice quality ranges from barely adequate to horrible. Why Samsung decided to put the speaker on the back of the phone - pointing away from your ear - is anybody's guess. I had to use a hardwired headset to be understood by callers most of the time. The voice quality when listening to a conversation was generally adequate, although the maximum volume was lower than what I'd want, especially in speaker phone mode. With my old non-smartphone Nokia I could turn on the speakerphone, put the phone down on the table and walk around the room and not have any problems hearing the caller or the caller hearing me - the Samsung never came close for voice quality.
Battery life wasn't so hot, but that's certainly something which I expected out of a smartphone with that fast a processor.
MetroPCS was almost useless - both the local store and corporate store. They kept telling me for a couple of months that the reason I wasn't getting 4G service on a consistent basis was their upgrades of their towers. I found out (on my own) that doing a factory reset solved that problem.
I did exchange my phone once and had to pay a $10 fee to do it through the MetroPCS corporate store with a 10 day turn-around to try to solve the GPS problem in case it was my phone which was bad. I received a refurbished phone (as expected) with the same exact problem - something which I never did track down was causing the GPS to fail once every couple of weeks. I tried isolating which application might have been causing a conflict with no success.
The only place where I am happy with the phone is anything which doesn't involve the GPS or MetroPCS. It works with most (not all) of the Android applications I've tried and is a pretty nice portable Internet terminal on WiFi.