I will say this. My biggest potential worry about him (or any candidate for that matter) is that he would be a squishy conservative when he got into office like George W.
If that happened, it would set our cause back tremendously. What I have researched on Perry suggests to me he would not turn out that way, but there are no guarantees.
If Sarah does decide to run and can demonstrate to me that she can run a serious, stable campaign, I would be very likely to shift my support. If she doesn't run though, Perry looks to me like the best of the bunch -- especially after Bachmann's collapse tonight.