It's a great watch! All functions perform great. I have an XL Bike frame so I have to mount the watch on the Stem of the bike instead of the handle bars so the watch can read the cadence sensor.
I've been using CS 300 for about a week now
and most things work as expected.
Pros:
1. Easy to setup - no wires
2. Easy to use
Drawbacks:
1. Transfer to PC. Roughly one try out of 10 succeeds. This is a known problem but I bought it anyway. Transfer from PC to watch works flawlessly.
2. Battery in speed sensor is not replaceable.
At least not officially. I've read people
managed to open up the sensor, replace the
battery and glue sensor back together.
The Polar CS300 is extremely easy to use. Tje installation process took about 45 minutes total. That was without ever having done an install before! The test ride was fun.
The wrist computer is large in size for wrist wear; however, once it is mounted on the bike the large size becomes an asset. It makes it easier to manipulate the buttons. I strongly suggest getting the cadence sensor to maximize your workouts.
The only downside to the product is the download/upload process to get to the data on the computer. The sonic upload works well once you get the hang of it. It would be nice though to not have to go to a website to get access to the longterm workout data.