Sarcasm aside and I'm DTW based so take it for what's it's worth but I think the trips are pretty similar from both. Mostly 4 day trips away from base. I find myself in LGA and JFK (and a whole lot in our base-but-not-a-base IND) more than I am in Detroit.

We do a bit of Canada flying from MSP, DTW, and some ATL actually out of the DTW base and I bet JFK/LGA are the same.

I think the question you have to ask yourself is really down to which one is the easiest to get to from where you live.