I went to the verizon store to sample the push to talk phones.  First
of all, the stores in the mall did not have any to try.  They had some
behind their display in a separate case but they were not activated.
Some sales people said it was just about as good as Nextel now.   Some
did not know because they didn't try it yet.   Several of the sales
reps asked "Why do you want push to talk?" and they said you can get
the same thing with in network calling.  So I got the feeling they they
were not excited about the feature.

The larger type Verizon store had some on display but the sales rep
said that they were not activated.  Apparently she was wrong because
they were indeed activated and working.   I started playing with one
because it had power.  There was one contact number in the list so
pressed the PTT button and said "hello".  I didn't hear anything so we
started to walk away.  Fifteen seconds later I was suprised to hear
"hello" come from a different phone adjacent to it.

I walked back and tried it again.  It pretty much had no delay AFTER
the first connection.  It was responsive.  I ended the session and
tried it again several times.  It consistently took a long time to get
the initial contact.  I timed it and it took 15 SECONDS!!!!  Yes 15.  I
could dial someone on the phone just as fast.

It is obvious that Verizon simply makes a normal cell phone call for
the PTT.
The PTT button simply creates and interface that makes it appear as a
walkie talkie.  All it seems to do is dial the person on the other end.
The other end automatically answers and throws on the speaker phone.
Not rocket science.  I don't see any significant improvements.  One is
better off dialing a person.

Something else to beware of...  The Verizon PTT phones will 'seem' like
they are fast.  You really need two to see what I mean.  You can press
the PTT button on one phone and it will immediately beep letting you
think that the system is ready for you to speak.  However, you won't
hear it on the other end until 15 seconds later.  This long 15 seconds
delay is only on the initial contact.  After that it's fast so its
essentially like dialing someone on the phone.

People that want PTT want it to act like a walkie talkie.  They don't
want to wait 15 seconds.

Bottom line is that Verizon's PTT feature is terrible.  However, their
coverage is still unbeatable.

So as of today, Nextel is the clear choice if you want fast responsive
PTT.  I don't like how it was so difficult to get sample Verizon's PTT
feature and I did not like how uninformed the sales reps were.  I got
so many stories from different people.

If you want push to talk - go with NEXTEL.
If you want premier coverage - go with Verizon.