We used it mid July, 46' flybridge mobo. It works really well, you can inspect the hull and gear while they powerwash it. If you get the last session before low water then you will be able to stay out the water for a couple of hours, if you have any minor maintenance jobs to do.
Only problem we had was we hooked their steadying rope in the prop on the way out, so had to be re-lifted to clear. The yacht before us did damage a stantion by snagging it on the jaws reversing out, so you need to be a bit aware and don't just trust the operators.