MEM is more laid back, with essentially 3 banks giving you 1-2 hours airport appreciation time in between banks. In comparison, DTW just keeps you going nonstop all day long. Your longest break might be 35 or 40 minutes on any given day. Needless to say, there are exceptions to these generalities.

If you like to get out of the plane, and sit down for a meal, you might not get too many opportunities to do so in DTW. Many many meals there are scarfed down during pushback/waiting for numbers. On the other hand, you are more likely to get higher credit/more days off in DTW, as there is no shortage of 7:58 credit days there.