I looked at the Mercedes c300 first but opted for the IS 250 instead. I have owned the IS 250 for 2 months now and the car is fun to drive. The 250 does get good gas mileage also. Rear seat legroom is minimal. One drawback is the paint. Already chipping on the front. I've owned other cars for years before the painted started to chip.
Push button start, keyless entry, navigation, dual a/c, handling.