I've had the Treo 750 since October. If you really need 3G then it's an OK choice. But it has lots of issues. If bluetooth is important to you then I would definitely say stay away from the 750. My main issues with it are:

1.) Bluetooth is incredibly unstable with my car (BMW). It will pair and connect will be get into a connect/disconnect loop, crash when making a call, or complete a call but have no audio.
2.) Bluetooth is unstable when using DUN. It will work but the data connection will remain connected but stop transferring data after 5 - 15 minutes. Sometimes a disconnect and reconnect will work, sometimes you have to reset the Treo.
3.) Sometimes it will work for a wakeup alarm sometimes not. Complete voodoo when it will work.
4.) Sometimes sound and vibration for calls and alarms stops. You have to soft reset it to get it back. Some people think this is really to voice dialing. They suggest turning it off. Nice features that you can't use it if you want to avoid problems.
5.) Other general stability issues. Not as bad as the Palm OS units. But not very good. In general the unit doesn't crash, but features just stop working.

To be honest, I'm trying a Motorola Q right now on Verizon. It was pretty bad when it first came out, but they have had two major firmware upgrades since then. It actually works pretty well now. It's tons more stable than the Treo 750. I used to be a huge Treo fan, but every model they have made in the past year has had serious issues and they had released almost no fixes in the past year. If stability is important to you I would say to stay far away from the Treo 750 until at least Palm does some serious firmware updates.