You can find a better price than those I believe. Try GPSCity.com or gpsstore.
Gpscity has the cs for $397.
The CS has a vertical trip computer which the C doesn't. Nice for hikers. Not much vertical data with the C at all. As well as accuracy with altitude over just satellite computed elevations. Most of Garmin barometer sensor units have a vertical trip computer.
The color screen is the best thing going on these. You can read them in bright sunlight,dim light,no light ,etc. Plus they compute much better than other models. Longer battery life,bright screen light for dim and dark conditions.
If you need to off load it they will command a good price on EBAY.
Do your home work and read about them to compare. But if your in a hurry just get the CS you can't go wrong.
Good luck