My 1998 C230 has the Signature Class warranty, which is called StarMark in the US.
I bought it because:
1. Priced the same as or lower than the 3rd party warranties.
2. No hassles on warranty claims. The dealer says it needs fixing, it gets fixed. Take my final drive seals for instance. One side was sweating VERY slighly. The dealer replaced all three seals right away, no questions asked.
3. Honoured at ALL Mercedes dealers.
4. Nothing but OEM parts used in your car.
5. If you resell the car, you can advertise "factory warranty" remaining. BIG bonus.
1998 C230 "Black Betty"