I went from time, to CB, to shimano. Won’t be changing again.
Even £20 shimano m520’s just go on, and on, and on. The cleats last several times longer too. There’s still plenty of float. My knees actually prefer them because you don’t have to force them round to unclip, and they actually click in/out, and at a consistent angle, no more guessing, or tentatively pulling up for the first few pedals, or coming to a stop and finding that the spring just won’t release at the angle you thought it would.
I had no problems rebuilding CB’s, they’re simple enough, but not having to do any maintenance at all is even better. And for £20 I’d just bin them if they did need it.
Time were OK, I never got more than a year out of the bearings though. They ate cleats like CB, and the bodies wore (although this seems less of an issue on the composite models than the aluminium ones).
The other advantage of Shimano over CB/Time is as the cleats wear out nothing change until one day they just fail. CB/Time get looser, and looser, and looser until they start falling out of the pedals. I think it’s because the bottom of the cleat wears out walking, but the hidden top bit does the cleating. Whereas CB/Time use softer metals as the cleat is moving around more under the springs, so the bit that interfaces with the pedal wears out.