Mesaba is a good place to work. Great bunch of guys/gals to fly with. The scheduling dept is a pain, so get off reserve as fast as you can. It has once again become the pilots responsibility to staff the airline, so plan on having your vacation cancelled.
I've been based in all three bases:
MSP: Professional attitude, on overnights you may eat a meal with the crew, that's it. Learn to walk down the hall looking at the floor, don't say hi to anyone. Lots of short flights, seems you are never in the air for more than an hour, only means you have to fly more legs.
MEM: Fun crews, like one big family. Not only do you hang out if there's time on overnights, a lot of them spend their days off together. Flying in MEM (on the Saab) has a lot of inefficient flying. Seems you sit longer than you are in the air.
DTW: First choice for me. A mix of crews here, this is the base for the best flying, and best schedules. Also the best place to commute from (depending). Chief pilots in DTW are the best, don't screw around and they will back you.
In my experience with Mesaba (6.5 yrs) they seem to want to do things the right way. If you do something by the book, or in the interest of safety you won't be hassled. Now with new airplanes coming, finally some growth opportunity.