I was in a similar spot to you 6 years ago. Got the call from United but lived in MSP. Took the job with United and realized quick that commuting sucks. Got called by Delta within my first year at United and took it. Yes msp is senior and it's hard seeing how senior I could be if I wanted ANY other Delta base. But it's still better than commuting. If you want to live in MSP the rest of your life, then go to Delta (unless your 50yrs+). The hard question is would you get to Delta quicker by going to United first....I would guess getting on at United would probably get you hired at Delta pretty quick but you never know what can happen. I loved working for United and to be honest if both Airlines had a MSP base I would have chosen United.