I have had the CS 100 for about 3 weeks now. The LBS also had CS 200's in stock. If you go to the polar website and do a comparo of the 2 CS100 models and the 2 CS200 models they have nearly the same features except for the "Cycling Intensity feature".

CS100 was about $100 bucks. (less with my discount)
added cadence sensor was about $40 bucks.

Please note the cadence sensors for the handlebar computers are different from the Polar watches. LBS sold me the wrong one at first but I still love 'em!

The heartrate monitor, "own zone", and callorie counter are my fav features.