He will attract those who want to see a Christian White man in the White House, and those who vote the way their redneck buddies want them to vote.
redneck voting peer-pressure?! how does that work, exactly? may need angus to come up with a believable dialogue between two shEt-kickers so that we can try to imagine it...But I am sure it wouldn't go over well in these parts, probably would be considered equivalent to sneaking a peek at your buddy's Johnson while he is taking a leak.
Casual prejudice against people who live in rural areas in the mass media probably accounts for much of what the original poster perceives as people "underestimating" Perry. Personally, I haven't seen a lot of that on this forum, but this meme does tend to occur everywhere.
I wouldn't vote for him or Romney - but he's a capable politician who might win the Republican nomination. And Romney is only slightly more capable of defeating Obama in the general.