You can only get ATL if youre on the CRJ.
IAH has both airframes.
You won't get either one right out of training, but you can probably get them within a few bid cycles. You'll be on reserve longer at either one since there is less movement at the small bases like that. So unless you live in one of them - you might prefer being based somewhere else. Commuting to a line is always better than commuting to reserve.