FWIW, around here (Northwest AR, a fairly old Cricket market), Cricket is absolutely abominable. They drop calls all the time, and the system is constantly so busy that you can't make calls. In addition, the coverage sucks. I suppose that if you don't actually need your phone, it's a good deal. It's certainly no landline replacement, IMO.
If you're in an area where Alltel offers their unlimited service, it's almost always a better deal, since you're using the same system they have for their "normal" customers, who won't stand for that sort of crap. Not only that, but in almost all cases I've seen where Cricket competes directly with Alltel, the area in which you can call with Alltel is much larger, and you can roam for 69c a minute. It is more expensive, however.