The C280 is better optioned, it came with automatic climate control and the Bose audio, along with possibly other things. I don't particularly care for either of the above, but the V6 in the 280 is significantly smoother than the supercharged 4 in the 230. It gives up a little bit in gas mileage, but is much more refined.

See if you can find a sport model in good shape, they're funner.