Walmart cellular plan/coverage good or bad?

Thinking about switching to the Walmart cellphone service (or whatever you call it). I have AT&T right now and use an iPhone 4 alone with 3 others in my family. I'm pleased with AT&T except for how much it's costing. Is the cheap Walmart service good or is it hard to get service and not worth it?

Straight talk? I'm pretty sure thats it. I've worked with 2 prepaid phone companies and i never left AT&T for any prepaid companies.let me just put it this way "you get what you pay for". Att might be expensive (I feel you) but even thought they say straight talk was is using verizon signal i just wouldnt risk it. And if youre disappointed imagine paying to get ATT service all over again!