I have been using Verizon's new PTT service on my V750 since the pre-release (about a week before the official release date.) I also used the older Verizon PTT service using a V65P several years ago.
IMHO, Verizon got it right this time. We have a group of about a dozen users, who have performed many tests of the service both in and out of Verizon's
EvDO Rev A coverage area. We have setup and tested the group connection features.
The most frequent complaints we have received, so far, have been concerning the speaker loudness and battery lives of both the V750 and the Boulder phones. The sensitivity of the outside keys of the V750, as well as the inability to disable (except for one-time disabling that must be re-set upon each time the flip is opened) the PTT key is a common complaint.
We have also done a few side-by-side comparisons of the new VZW PTT service with Sprint Nextel's Direct-Connect.
Feel free to contact me with any specific questions.