He's staunchly conservative, as opposed to Romney who is going to have to explain away his healthcare bill in Mass. He's got a record that includes growing jobs in Texas while other states were losing jobs, and he certainly looks the part. He's also a man, and to this point he's untested. He's pretty much skated through the past few months unscathed while other candidates have been taking beatings.
The problem with perry is that the jobs he's created are usually well below livable wages (think fast-food jobs) or by allowing companies to operate with very few regulations in either pollution or safety, therefore you have dangerous companies moving out of other states, and into Texas so they can practice sub standard business.
He has a ton of momentum though, and he's a super-Christian, so he'll appeal to the very far right.
He's going to be a force to be reckoned with.