A friend of mine has a tru trac the front axle on his F-350. Works great you can still kind of turn on the street with the hubs locked and it spins both tires. Made a huge difference with plowing.
I have a detroit locker/no spin. It is a full on locker and I really like it. I don't floor it around corners, it behaves fine here in MN. I got it for the snow and so far so good. I rarely use 4wd now. Hope this helps.