I've only had my PT for 8 weeks, but I think it's been extremely valuable in helping me find my potential.

This is my third year riding, first year training and racing. So, before this season, I'd never had real sprinting experience on the bike. My legs/body simpy didn't know how to sprint, so I've been using the PT to help me fix this weakness. Four weeks ago, after a few races:

peak=953w
5s=840w

Yesterday, after 3 weeks of trying different gear ratios, positions, etc. while using feedback from the PT:

peak=1234w
5s=1100w

Again, I'm not attributing these gains solely to the PT, but it certainly has helped me 'learn' to sprint better.