There are so many variables that nobody can give a definitive answer.

Do you live in ATL? If so, reserve is a good gig, other than it makes it more difficult to manipulate your schedule as you cannot ELITT reserve blocks (fixed next contract hopefully!!). Reserve at SWA is way different that other airlines.

If you don't live in ATL...then I'd be looking to commute to a base like MDW, HOU, BWI, or DEN depending on where you live. You'll likely have much more relative seniority in those domiciles.