I always check Amazon for reviews. Here is a link to the 9100:
http://www.amazon.com/Singer-Profess...dp/B00EXSTMBS/
I would just say that the "Professional" in the name is pure marketing. This is a $300 or less machine, so is considered low-end. In that price point, I would normally not look at a Singer at all as their current reputation is pretty bad, especially for tension issues. I would be looking at Brother machines instead.