If the car checks out well, it seems to be a good deal.

W210s are on average fairly inexpensive to maintain. Be sure to check for rust. Other than that, make sure the crankshaft pulley/harmonic balancer is updated. Other W210 problems are the Mass Air Meter, rear window regulators, weak sunroof motors, and a few other things I'm fogetting. I'm sure others will chime in as well. We have a W210 E320 and an E430, both are fantasic cars.