Welcome. Are you LAMA?

Don't know much about ATL yet, it is just opening up.

SLC has a LOT of pilots living in domicile...it's common for them to delay upgrade until they can hold a decent line as a CA, so there are some very senior FO's. Recently they massively reduced the number of 4-day trips and increased the number of two day trips. This is good for pilots who live in domicile (home more often) and the company (less per diem and hotels), but bad for commuters who don't want an overnight break in domicile where they need a crashpad. I am still able to get mostly 4 days though. Both UAX and DAL trips start here, the DAL trips are pretty good, but the UAX often flow through places you don't want to go (ORD)

Historically, seniority (and schedule) has been better in DEN, due to super-senior folks in SLC but this is less true now with all the SLC growth. The downside to DEN is UAX trips that flow through ORD...lots of short, nasty legs and Wx potential.

The junior base is MKE anyway. Either DEN or SLC would be good if you live there, as a commuter I would probably take DEN.