This pattern is now years-old stemming from merger-related issues, but I have long-term status in both UA and DL. I was a CO flyer, and prior to the NW-DL merger, had booked all of my CO (and later, UA) flying to the NW program. Walked away from 1.2MM in DL to fly UA primarily after the merger, being based in CLE.

"Fortunately" (though I'm not sure that's the right word for travelling as much as I have to do), I'm still in the sky frequently enough that making status on even 2 airlines isn't a big deal. So I'd guess you can call me a "Kayaker". I buy J tix spread out between UA and DL + alliances -- typically UA TPAC and DL TATL. Between that spend, I can reliably make 1K on UA and Plat or Diamond on DL every year.

For domestic/economy tickets, I buy whatever seems best at the time. Try to avoid UA's RJ145 fleet like the plague. Try to avoid flying DL through JFK. Sometimes I'll engineer for a likely upgrade. Other times I buy whatever is going to get me there/home quickest.

For points, I don't even bother playing the game anymore. Between Chase UR and Barclay Arrival+, my freebie travel comes almost entirely from cc programs. My airline-direct points are used for upgrades, or I give 'em away to friends & family as gifts -- my traditional wedding gift to a family member or close friend has become 2x J tickets anywhere in the world they want to go.

Heck - I've even started flying F9 and B6 out of CLE occasionally. Buy all of their upgrades, and you can have a pretty decent flying experience at still a fraction of the price of either of the majors. Book my ticket on my AmEx, and I even get 5x points out of it. I'll take an exit row or a Stretch seat on F9 over an aisle on UA's RJ145's any day.

Basically, the airlines made it all about money. Well, congratulations guys... it's now all about money, and where I'm going to get the best value from it. And it ain't giving ANY one airline all of my travel budget anymore!