A few points to think about:
- This is still a CDMA phone with no automagical chipset in it, meaning that you can't talk and do data activities at the same time. That may change as LTE rolls out and a new version of the iPhone is released, but as it stands with the iPhone 4 on Verizon, that's just how it is. If you're already a Verizon subscriber, you may already be used to this and it won't be a big deal to you, but if you're like me on AT&T with an iPhone 4, then consider this your fair warning.
- The mobile hotspot option is really cool. In general I've found that most of the places that I go, Verizon's 3G data network is faster and better than AT&T -- we use Mifi devices from Verizon for mobile data. I'm guessing, however, based on my first bullet, that when you are using the iPhone as a hotspot, you can't also engage in voice activities; not having played with the device, I'm not sure if it prioritizes voice over data, but if it does imagine serving up data to a few devices with your iPhone, getting a phone call, and knocking all of those devices offline.
- None of the specs for the Verizon version indicate SIM compatibility or a GSM radio, meaning that you won't be roaming on any overseas networks unless where you're traveling has a CDMA network. Perhaps not a big deal to many people, but worth thinking about -- note that AT&T's GSM network is the standard for most of the rest of the world, so international roaming on AT&T is really easy.
- Keep in mind what happened when all of those iPhone 3Gs rolled out on AT&T's data network. Verizon says they've been ready to handle the data consumption increase since 2009, but only time will tell if that's actually true. I hope it is for the sake of my Mifi.
- Some pictures floating around out there make it look like the switches on the side of the Verizon version got moved slightly, but noticeably on the left side of the device. If that is, in fact, the case, then you might actually need a different case than what fits the AT&T version -- worth thinking about if you've got some $$ invested in AT&T iPhone cases and are making the switch.
- Outside of the personal hotspot function, the iPhone 4 on Verizon doesn't appear to do anything that the AT&T version doesn't do. Most importantly, it runs the same iOS and functions from a software perspective in the same way, so if you don't like the iPhone experience on AT&T, you're not going to like it on Verizon either.
- The past iPhone upgrade cycle has occurred in the June/July timeframe and no one besides some folks in Cupertino really know what might be coming this year. It's impossible to look into the crystal ball and know if this year will bring a "S"-type upgrade that was done with the 3G, if we'll be looking at an iPhone 5, if any of the upgraded devices will be available on Verizon or AT&T or any other carriers, etc. Is there a possibility that an iPhone 5 will be released in July and that it will be available on Verizon? Sure, it's possible.
If you are an AT&T iPhone 4 user and you did the upgrade last July, I do recommend that you do the research around what your early termination fee might be with AT&T and how best to settle out with them. A quick Google search showed me that AT&T has little sympathy/mercy for those that switch to another network mid-contract and they apparently will forward outstanding amounts to collections without hesitation.