I have a detent and a non locking. I like the detent best. The detent will still let you change position with pressure while on the bolt. The head position stays where you set it otherwise. The non locking is too loose (can't tighten this one) and a heavy deep socket can flop around. It makes positioning in tight places tedious. The detent is my go to and the other doesn't get used much.
One year later and I still vote both, each have their place. As IGN says, with the wrenches I prefer non-locking, I don't even own a locking wrench, well, except all my regular wrenches, they are locked in position all the time.
I prefer non locking for 1/4 and 3/8 drive and locking for 1/2 drive. The weight of some of the 1/2 sockets just overcomes the flex tension on the 1/2 head sometimes.