Tony, I ran the 637 briefly when I got just to make sure that it was OK. It has good torque, but saying it should be an "MS200 Killer" is a long stretch! The 200 has been and will be the benchmark for top-handle saws for a while. The price of the used 637 was the reason I bought it.
Given the the choice of having to buy "one" top-handle saw the MS 200 would be my choice!
I also like to try new saws..........someone has too...........given that, the 637 was a cool buy!