Read Sam Smith's comments on driving the 2008 Mercedes-Benz C300 4MATIC.
This thing has an amazing amount of grip. I clawed through a couple of inches of snow this weekend, convinced the C-class was on some top-shelf snow tire, only to look on Sunday morning and see ordinary Conti SportContacts. Crazy. It just gets up and goes.
Positives: Linear power delivery, quiet on the highway, interior is HUGE steps above that of the last C-class. Decent (but not great) stereo. Transmission is calibrated fairly well in sport mode - responsive when you want it, unobtrusive when you don't. Damping is impressive; you can bang over speed bumps and potholes and not feel any harshness, but there's still a tightness and chuckability missing in larger Benzes.
Negatives: Wooly steering feel, especially at speed (again, I thought there were snow tires on it). Engine is coarse and somewhat unrefined, saved only by an excess of sound deadening and a good transmission. Lack of headroom - I'm 5'10", and my hair almost touches the headliner in the front seat with the seat adjusted all the way down. That stupid nav screen - it seems clever at first, but then just gets annoying, as it's high enough to be distracting. (I want a display that doesn't make me flip through instrument cluster menus when the main display is hidden.)
Also, I'm assuming that you can't turn stability all the way off? It's fairly harsh and abrupt in its "save you" intrusions - it tends to yank you back at the limit with a big 'ol stab of brake. That said, crazy crazy amounts of steering lock and throttle in the snow seem to make it give you a little more leeway...