This morning, Verizon announced that the iPhone will be available on their network next month. The rumor, started when the very first AT&T iPhone dropped its first call, has finally been confirmed just four years after it started. Living in L.A., I don’t know a single person who doesn’t love their iPhone, and despise AT&T. Many have vowed for years to switch to Verizon as soon as the iPhone was available on its network.

But is that really such a good idea? If millions of people switch from AT&T to Verizon, will Verizon’s pastures still be greener, or will the influx of iPhone customers overload Verizon’s network just as it has AT&T’s? And how overloaded is the network, really?

Living on the 7th floor of a building on the edge of the Hollywood Hills, I’m lucky if I can get 1 bar on my iPhone. When friends come over, they have the same problem. Yet earlier this year when I traveled across the country, I found myself with 5 bars / 3G almost everywhere I went. I got better reception in rural New Mexico than I did in Hollywood. What the hell?

It turns out that people don’t like living near cell towers. In big cities like L.A. and San Francisco, it’s very hard to get a permit to put up a new antenna, even on top of a building where nobody will see it. Even though there’s no evidence that cell phones can cause brain cancer, it’s still a popular myth. And if one cell phone can cause cancer, then what happens when you have a whole tower broadcasting right next door to you??? Ack! Panic! Not in my back yard! So in the two cities where the iPhone is most popular, cell companies are stuck in a situation where they can’t add more coverage.

So what will happen when everyone in L.A. switches to Verizon? Will their network be able to handle it? Have they managed, over time, to set up towers in places where AT&T could not? I’m thinking “no.” I’m thinking people will very quickly find that if an area is an AT&T “dead zone,” it will be a Verizon “dead zone” as well. And that Verizon’s network is no better prepared for the influx of iPhone users than AT&T’s was.

The biggest problem with a Verizon iPhone – and the reason I’m surprised Apple made one – is Verizon’s network format. In the U.S., AT&T and T-Mobile use a format called GSM. Verizon uses an older format called CDMA. All the cell companies are scrambling to update their networks to newer formats, but right now, Verizon’s is the most out of date. CDMA networks do not allow a phone to make a call and receive data at the same time. That’s important. I’m making it its own paragraph:

CDMA networks do not allow a phone to make a call and receive data at the same time.

GSM networks allow this. Now, on the surface, that might not seem like a big deal. “I don’t normally make calls and surf the web at the same time.” Sure, neither do I. But it isn’t just web surfing that uses data on the iPhone. Things like the Maps app use it as well. But I could come up with a dozen examples where you might want to be able to use the phone and receive data at the same time, and you’d say, “Oh, I’ll never do that” to all of them. And that might be true. But there will be something. If you’re used to a GSM iPhone and you get a Verizon one, there will be something you’d expect to be able to do that won’t work because of the voice/data restriction.

To be clear, a Droid phone running on CDMA will have the exact same problem. (The Droid market is already hopelessly fragmented. As developers have to create different versions of their apps for more and more system/phone combos, the user experience will suffer more and more. You can get a perfectly cromulent iPhone 3Gs for $50 now. There’s no reason to buy a Droid.)

But what about Verizon’s new LTE network? Yes, it will be a huge improvement over CDMA, and allow voice/data at the same time, and be faster, etc. But you can’t get a phone that works on it yet. Sure, a few phones have been announced, but they won’t ship until the middle of the year… right around the time Apple updates the iPhone. And I think we can expect the new iPhone to work on Verizon’s LTE network.

So here’s what I’m going to do, and if it makes sense, maybe you should do it to: I’m going to stay with my 3gs iPhone on AT&T until the summer. Around June, we’ll find out what the iPhone 5 can do, and if it will indeed work on Verizon’s LTE network. If that’s the case, I’ll consider how good/bad AT&T has been recently – for me, where I actually make calls – and I’ll reflect on what friends have told me about their recent Verizon experiences. If people are still positive on Verizon, I’ll switch to their network and get an iPhone 5. If not, I’ll still get an iPhone 5, but I’ll stick with AT&T.

I guess the bottom line is, unless you’ve got a white-hot hatred of AT&T (and I know many of you do,) I’d wait and switch to Verizon when an LTE iPhone is available (most likely in June.)