Anyone here have experience with either the Boost Mobile or Virgin Mobile unlimited plans?

I am thinking about changing cell phone plans. I have AT&T right now, but I would like to go to an unlimited (or nearly so) plan that includes Web access. I primarily want to check my 2 emails, one of which is for work but cannot be accessed through a regular phone email client; Web access is the only option. I also want occasional Web usage, although it might turn into heavier use.

AT&T is quite expensive for their data plans; it’s going to be $30 for it using most phones I would consider, so the total plan would be over $100/month.

By contrast Virgin Mobile has a $49.99 unlimited plan for voice with an additional charge for data ($5 for 20 MB/month and $10 for 50). And Boost Mobile offers a plan with everything for $50.

I talked with a Radio Shack salesman who seemed knowledgeable; he was not too hot on Boost’s Web speed; intimating I wouldn’t like the service. But he’s a salesman (he tried to swing me over to Sprint). I want an unbiased opinion.

So, anyone here use either unlimited service, or at least one of the pay-as-you-go versions of wither carrier? What do you think?

Update: This company just started offering $50 unlimited talk/text with 100 MB monthly service, all on the regular Sprint network. I’ll give them a try, then come back here and either sing their praises, or warn everyone off.