Any current or former owners of one here? I was always a BMW guy - still am actually - I just figured it was time to try something new. I've owned an Alpina B7 which was awesome, several 3-series variants and an e36 M3 currently, and wanted to get into a Mercedes. I bought an S55 AMG a couple of months ago and I'm knocking on wood while I type this, but wow! What a car! Tremendous value for the money, great quality build, very fast, very good looking, and they sell for a fraction of the cost of a nice E39 M5. I'm sure people might say apples to oranges, but I've seen nice E39's sell for upwards of $50k with low mileage, while an S55 with similar milage sells for less than half. I guess we all like what we like, and the E39 is an awesome car, though it's hard to argue the value propostion of the Sonderklasse.
Never had the S55 but I have owned the C55, E55 and currently the ML63 and they are all amazing (as long as you let someone else take the initial depreciation hit)