The YBB is hard to beat- I've owned mine since fall of '07 and have loved every ride on it. I'm on the other side of the country so I can't offer you a test ride, but I can offer my insight.
The YBB is really a lightweight full suspension bike, especially when paired with a ti post. On the road you can feel some slight movement of the suspension when spinning on smooth surfaces, but on the trail it's not noticeable that it's doing anything other than smoothing out the terrain. Handling is amazing, the ride quality is superb and it's a great bike for XC races and long days in the saddle. I've put mine through several 50+ mile races and it's been the perfect blend of light weight, smoothness and efficiency. Most people who have owned one would tell you the same.
It's not a hardtail, so if you want a frame that's about .3-.5 pounds lighter, a little stiffer and less compliant then get the Rigor. By hardtail standards the Rigor is by no means harsh, but it's not a plush duallie ride by any means. The two seem close, but they're very different bikes.
The only time I would consider the Rigor to be a better option for me was during short track and weekly training races that are less than an hour. In those events the out-of-the-saddle efforts and torque might give the Rigor a very slight edge, but not enough for me to consider trading in the traction advantage and compliance of the YBB.
I also have more detail on my blog- http://www.pro-35.blogspot.com.