It is just Sprint. Sprint is using a higher frequency for wimax, it's not wimax itself but the frequency they are using for it. Verizon isn't going to have this issue.
Again, it's location dependent. Sprint's network isn't as good as Verizon, nothing new there. It has areas that work better than others. If you travel a lot I would spend the extra money and go with Verizon. For those of us who don't and have good Sprint coverage where we frequent Sprint is cheaper for comparable service. If you have your phone set-up properly you can roam on Verizon towers. Though when roaming you are at the bottom of the food chain behind Verizon customers on those towers so it's not going to be like it's a Verizon phone but better than not being able to do so.
Bandwidth isn't going to be a problem for Sprint anytime soon. They have a ton of it and they are not going to have a large enough customer base to stress it for a long time. I will venture to say never, the company as it is will fail before that happens. I have been a Sprint customer for a long time and love the service I get for the price I pay but in the end I think the decision to stick with Wimax is going to kill them.
The notion that because Sprint has fewer customers that they therefore have much better bandwidth availability is just nonsense. Yes, they have fewer customers but they also appear to have fewer towers so the number of customers per tower may in fact be higher for Sprint that Verizon.
I just did a couple of speed tests here in Plano/Richardson TX and here's what I got:
3G: 46kbps down/351kbps up, 88kbps down/260kbps up, 82kbps down/198kbps up.
4G: 2462kbps down/91kbps up/2854kbps down/968kbps up
I used three different servers to get a better average.
The first test, at 46kbps down, is less than you can get with dialup!
I do expect the problem will be less when the 4G build-out is more complete, but then again, there maybe more customers using more data by then.
The bottom line is that it is less a question of the number of customers as it is the ratio of towers/customers.
Brian