As other posters have stated, we need to know more about your travel habits to provide guidance. I'll just walk you through my decision earlier this year to switch from WN (Southwest) to UA (United).
Previous Travel Profile:
- 100% domestic
- Mostly traveling to destinations in the Midwest, Northeast (primarily LGA), South, or Silicon Valley (SJC, SFO, OAK - preferred in that order)
- Was about to get married
(Southwest) - as I was traveling a lot (and all domestically), I valued being able to get Companion Pass (CP) on Southwest since I wanted my wife to be able to travel with me whenever possible. Southwest has a fantastic route network out of MDW and I didn't really care about being upgraded as CP probably saved me $6,000 in terms of free travel. Remember that CP also applies on award travel so I was able to use my Southwest points for free travel ($10 in fees) for my wife and me. Also, MDW is significantly more convenient than ORD for folks who live in the downtown core of Chicago.
Current travel profile:
- 10% international, 90% domestic
- Primarily traveling to DC (DCA, IAD, BWI - preference in that order), SAN, SNA, MSP, PIT, and FLL/MIA
- Wife is busy and can't travel with me much now
Decision: Primarily UA but no true loyalty
- I'm focusing on keeping all my international travel to Star Alliance (*A) of which UA is a part but given that UA's low-level elite benefits don't seem super tantalizing, I've flown a decent amount on WN this year. While MDW may not have the amenities of ORD, I do appreciate being able to get in and out quickly and for all the hate that WN gets from FTers, it's still a great airline in terms of reliability and friendliness. WN's customer service is second-to-none but at the end of the day, UA does have some fantastic international mileage redemptions and the *A network is fantastic so all things equal, I will choose UA. When UA is more expensive or less convenient, I will take WN, AA, or even DL (sorry, not willing to fly Spirit).
I am not one of those people willing to fly one-stop flights to earn more miles. We live in Chicago. This is the best city in the US to live in for frequent fliers. Fly direct, nonstops everywhere and enjoy the time you save.