I've got one maine-angus cross. He's very nice. He's gentle. His calves are light at birth, and very blocky. I'm afraid too blocky. I've asked the same question on this board before and got the same replies as I've just stated. The calves grow a little slow, but eventually get huge. Might be nice for retained ownership, but growing a little slow for me selling weaned calves.
The thing with Maines is you almost have two breeds within a breed. Maines are the prefered base for show steer folk and with that sometimes the genetics are geared for non real world attributes like hair, small frame, etc.I think performance mains are awfully hard to beat and i can't think of anything I would rather feed than f1 main angus. Historically one of the drawbacks was lack of calving ease, but that has pretty much gone by the wayside with selective breeding. i guess another drawback is a chance at some chrome on the wheels once in a while.
The great thing about mine is I am getting black calves out of him. I put him on some Braford cows with mixed results, but I've two angus cows also. The calves they are spitting out from that bull are outstanding. A hair blocky, but otherwise picture perfect. Black with white faces, sometimes chrome wheels. Eye candy for feeders.
I really like Maine cattle... we've had a few heifers in our herd over the years, and they've had good marketable calves, and a few show calves as well. In fact, while I'm shopping for that "Perfect" Simmental bull to replace the one I lost in December, we've got a reg. Maine running on the cows.
I think the biggest market for Maines is probably the club calf market, but don't overlook a Maine for a good pasture type animal as well. They are generally quiet natured, and good growthy calves.