Well, the first sign of the apocalypse is upon us - a carrier other than AT&T will offer the iPhone. And while the thought of having an iPhone that works reliably is enticing, I think there's a compelling reasons to stick it out with AT&T in the short term.
Verizon's CDMA network is getting long in the tooth. When I think about all the existing Verizon subscribers (and disgruntled AT&T ones) that are suddenly going to be swamping that network with shiny new unlimited data plans, I can't help but feel that the criticism that fell upon AT&T will be visited upon Verizon as well. If they can pull it off and things are smooth after a few teething months, count me in as a switcher. I think that February and March will be an interesting time to be a Verizon customer.
Having said that, I'm the first to admit that AT&T's service is poor. Their two big claims of fastest data speed and simultaneous voice/data are merely an attempt to emphasize the minor (and arguable) benefits of their network. Nowhere have I heard them tout their network's reliability.
My personal experience is that a good portion of the time, my idle phone doesn't even ring and a voicemail magically appears from the person whose call I missed. So I'm having a hard time caring about simultaneous data and voice. Perhaps it's a case of not knowing what you have until you lose it - at the moment I'd gladly trade it for a phone that consistently rings when someone calls me. For those touting that the data/voice feature is critical for GPS - I personally wouldn't put my faith in AT&T's data coverage when I'm in the middle of nowhere and need to get somewhere. That's why I use GPS software that has pre-loaded maps.
As for data speed, I've found that my phone functions worse in terms of coverage and reliability when I'm in 3G mode. My solution is to use Edge 90% of the time - clearly I'm not benefitting from the "fastest data network."
I really hope Verizon pulls this thing off. Competition is good and I think AT&T has rested on the laurels of exclusivity for too long. I'd like to see both carriers fight to keep their subscribers happy.
For now, I'm going to stick with the known quantity of AT&T until the dust settles and I can make an informed decision.