I recently switched from a Treo 650 to a Sprint 7130e. I also tried the Verizon 7130e for 2 weeks before the 7130 was released on Sprint.
My Treo experience was good, but I was forced to switch due to my company going to a BES as the only supported wireless e-mail allowed. However, I viewed and used the Treo as a smartphone - a cell phone with e-mail capabilities. I didn't load 50 3rd party applications and try to turn it into an iPod, a movie player, a microwave oven, and an electric back scratcher as many people in the treo forums go on and on about. As a smartphone, it worked fine with some minor phone voice quality and reception complaints. The Sprint Business Connection desktop e-mail forwarding worked great. If Sprint offered and supported BB Connect, I would have stayed with the Treo.
With that said, I really like the 7130 and use it in a similar fashion - as a phone with e-mail capabilities. I can definitely say that the Sprint 7130 is more stable than the Verizon one I used - no random resets, no in and out EVDO as was covered in these forums, and the phone voice and reception quality is comparable to any other cell phone I have ever owned or used. E-mail with BES is rock solid and OS integration of contacts to call, e-mail, SMS, or MMS people is awesome.
If I have an overall point to your original question its that the Treo 650 was not drastically better or worse than the 7130 I am using now and the Sprint 7130 has been more reliable and stable than the Verizon one I used.
Sprint BB 7130e 184.108.40.2068
BES 220.127.116.11 (Lotus Domino)
former Treo 650 user