Well, I hesitate to say this, I typically won't get caught up in the bottom paint debates, along with varnishes and anchors. However, I hauled a boat last year that had Propspeed on it, and the jist is, we were amazed. Poor boat had a million blisters on it, as the owner had bought it freshwater, slapped a little ablative on it and sailed. Knowing this bottom would need surgery, and it did, whoo boy, but the guy had put the propspeed on it because 'it was there'. It was the only thing under that boat left intact. Thruhulls beat out, transducers leaking, head stopped up, but the prop...wow. I should have taken a picture of it, and I might have amongst the thousand I take a year. But that silly prop looked like the day they dropped it in the water, you could literally wipe it off with a Kleenex.
I don't know, we'll launch over fifty boats a year, and if the owner doesn't specify, we'll 'experiment', figuring the boat will be back next year. (We have a huge repeat business of happy owners). We have put on most known substances, including the hards and ablatives that we know full well won't last a month. None of it does. One guy even tried surfboard wax. Go ahead, guess how long that lasted.
A lot of our clientele is very large boats. It's not uncommon to seat a 48" wheel here. As a rule we buff them to a mirror shine with high speed Scotchbright pads. And that is all. The tug operators laugh at coatings, because those old pros know that nothing is gonna stay on there that long. Out of all of that though, despite every known prop 'cure' that is available, I would have to vote the Propspeed though. It is the only thing that I have ever seen that will come out of the water intact.
Properly applied of course..