I am going to be completely honest with you and I may get flammed for doing it. Ask yourself these questions:
1. AM I comfortable with doing software upgrades on the storm?
2. Do I need a Blackberry or can I use another smart phone?
The reason why I say #1 is because the .75 release from my experience has been awful. It is extremely slow however it is stable (if that makes sense?). If you are comfortable with doing software upgrades to phones I would say go for it.
Number 2 there are times I wish I was on AT&T just because of the Iphone. I look at the app support for Iphone with the integration of Itunes and drool. Now RIM is working toward a solution to this and I am confidant that soon we will have alot of apps but we need some developer support for it first.
There are just my personal opinions. Storm is a great phone but you just need to have some patience. Verizon is an amazing network which is why I am sticking with them (I live in the b00ney's).