I ride as slow as possible while still maintaining a good wake. A lot of it depends on the weight in the boat though. The more weight in the boat, the faster you can go with a clean wake. If the wake is small, I find myself slowing the boat down too much, forcing me to sit too deep in the water.
If I am working on spins that I want to take straight up to avoid landing in the trough, I usually slow the boat down.
What it comes down to is that I am a picky SOB that needs everything to be perfect
I wish I was one of those people who could ride well behind any wake.