From a BTS perspective, my understanding is that the transition from Rev.0 to Rev.A is primarily just swapping out a transceiver card at the site. I would imagine most of the delay between Verizon's Rev.0 and Rev.A general purpose rollouts was due to QA and observing the behavior of smaller scale test rollouts before a full production deployment network-wide.
From my perspective, that seems pretty generalized, but not inaccurate. It does ultimately boil down to replacing DOM cards with DOM-A cards to turn the tower in to a Rev.A accessible tower. There's lots of infrastructure and software changes that need to take place first, though. I'm not at liberty to discuss the changes, and even if I was, I only understand a fraction of what they are.
I don't typically see >1mbit reverse link speeds in practice (though >1mbit is within spec in ideal circumstances); it is more common that I observe 60-80KBps in locations with a solid link to the tower, much less at fringe areas. It is certainly much improved over the 144kbit/sec max reverse link in Rev.0, though.
I clarified the Rev.A/5.0 thing; Rev.A is just QoS, 5.0 will introduce broadband on the reverse link. I can't talk about specifics, but 5.0 should be going out soon. Let's just say we're at the "get in the van and see how far away it works" stage.
Even if you have a Rev.A handset, you're not guaranteed to be talking to a DOM-A on the other end of the tower. They're becoming more widespread, but it's a slow process. I know parts of LA and Chicago have them, but the only reason I would ever find out is if there was an outage, so they're probably more widespread than that. Where are you located?
I'm sure you already know this, but it's also important to take in to account the amount of overhead there is in IP and the layers below it. This is especially important to consider in wireless communication, where it's pretty rare, even with a strong signal, to get a message through on the first try. When broadcasting, there's no guarantee that anyone is listening - and even if they are, you can't be sure they're ready to accept what you have to say. Retransmission is inevitable, and it's the primary reason that QoS was introduced in Rev.A - the target of Rev.A is to make wireless data readily accessible, not just possible as they did with Rev.0.
I was in a meeting the other day, and it sounds like they're actually going to go through with Rev.B, after they abandoned it a while ago.
Being that I am completely ignorant in this area, in layman's terms what benefits will Rev.A offer?
Does this involved all phone or more specifically PDA phones?
Quality of Service. Outgoing packets are prioritized according to some logic. It will affect any EV-DO Rev.A enabled device.