I used to take this road every day before I moved to Fribourg... It's my little race track !!! The quality of the road is perfect. The number of curves is pretty low (6 to 8 depending when you stop), although they are the best ones I've never took... And once you've arrived in Fribourg, just take the same road again, and go back to Posieux, Priceless !
It starts with very long curves and high speed between Bulle and Montbovon, a must for the sport bikes, really great. After that, you get into a small valley with smaller curves which is perfect for roadster. The average speed get down to 80 km/h. The quality of the road is exceptional until Montbovon, then, in the valley, it's still very good, but there is some little muggles on the raod from time to time.