We currently use Nextel, but are unhappy with the coverage area of their service. We also use Verizon for cellular only service which has much better coverage in our area therefore, we are considering switching to Verizon push-to-talk service.
I'm wondering if anyone uses the Verizon push-to-talk service and what they think about it.
I have another question also, can it be used to access Nextel push to talk or only verizon?
Unfortunately, the're not compatible. You have to use one or the other. 
Verizon makes it easy; For $20 a month you can add unlimited PTT to any cellular plan. My only gripe is the fact that they offer (1) PTT phone and it's that cheesy feeling Motorola V60.
That's a shame, for what you pay you would think that you could use them like amy other service, I guess it might happen further down the road. 