Seems an honest enough ad. (doesn't claim the wheels are genuine AMG, for example).
If the car checks out in the metal it could be a reasonable buy. A 500 would be a safer option though, IMHO, and only fractionally slower 0-62. Haven't got the pre-facelift figures, but for the 1997 models the 500 is 6.5 secs and the 600 is 6.1. Fuel consumption is a bit academic, but the combined figures are 19.8 mpg for the 500 and 18.2 for the 600 (1997 figures again).