In reply to woolsack:
I have one on my tri bike. Once you've tried it, you'll never go back to a traditional saddle for a TT position whilst you're still in possesion of a pair of testicles.
A relative of mine getting into triathlon last year found it impossible to even try for a decent aero position due to cysts on his balls, until I brought this to his attention... he recently completed his first ironman on it with no problems.
I've stuck with a slightly more traditional saddle on the road bike for now though (specialised toupe), as I like to move around a bit more when I'm upright (and the body geometry design allows plenty blood flow unless you're right on the nose).
Make sure you get it set up right though, it'll be positioned very differently to your normal saddle... there's loads of videos on youtube showing how to set it up. Worth spending a while on the turbo trainer tweaking it just right.