I just got a new Polar CS200 cycling computer. The CS200 combines a traditional cycling computer and a heart rate monitor into one single device.
I have been using a combination of a Polar A5 heart rate monitor and a Sigma Sport BC1200 bike computer in the past. Recently the T31 transmitter (that came with the A5) stopped working and instead of simply replacing the transmitter I decided to spend a little more money (and use a voucher I received more my 35th birthday) to get a CS200.
Why did I choose a Polar CS200?
First of all, I was looking for one single device that combines both a cycling computer and a heart rate monitor. I prefer a device that can be mounted on the bike's handle bar because it allows you to read the display without the risk to smack your head into a tree. I normally never wear a watch so there is no compelling reason to go for a watch model like the CS300 or the S725X.
Secondly, the CS200 comes with the WearLink 31 transmitter which is a lot more comfortable than the T31 transmitter. It is coded which reduces the possible interference with other transmitters in close proximity. Additionally, you can detach the sensors from the actual transmitter which prevents accidental draining of the battery. The battery itself can be replaced (which is not possible with the T31).
Thirdly, the CS200 remembers your last seven training sessions. The CS100 and my old A5 only remember one session. If you (or your two year old kid) happen to press the start button by accident, you erase the data of your last training session.
Finally, the CS200 allows you to upload your exercise data to the Polar Personal Trainer website. I still have to find out how useful this really is but it probably beats writing down all exercise data by hand.
So in the end the CS200 seemed like the best solution. The CS100 comes with an inferior transmitter and no way to upload exercise data. The CS300 is a watch model (and costs about 30% more).