Right now, sitting in our drive/garage are two RWD cars, one AWD car, and one FWD car.
The low power FWD Mazda is a mountain goat at slow speeds in poor traction conditions. This is due in part to it's FWD, but mainly because of it's low curb weight (contrary to SUV dictum, low weight is BETTER for handling, acceleration and braking in snow and on ice) and it's aggressive snow tires. Try to hustle the Mazda, and it understeers like a pig, and will frustrate any drive with even a modicum of skill.
The RWD C230 is not as good off the line in icy/snowy conditions as the Mazda, partially due to it's RWD, but mainly thanks to it's poorer traction snow tires.
The AWD Subaru is amazing thanks to true AWD and Blizzak tires. Truth be told, I'd rather have a RWD car on Blizzaks/Hakkas than an AWD car on all-seasons. Tires make the difference! However, in slippery conditions, the AWD system aids handling and has a well balanced feel. Since WRC cars spend most of their time in poor traction conditions and have gobs of HP, AWD makes perfect sense.
The FWD Mazda sucks on dry pavement. It's 65/35 weight distribution is awful, and the steering feel is terrible thanks to the dual job of pulling the car and steering that the front tires have to do.
The AWD Subaru is much better on dry pavement than the FWD Mazda, but no thanks to it's AWD system. Well, partially I guess. The added weight in the rear of the driveline makes it a bit better in the handling department. However, there are really no gains for AWD on dry pavement. It's a foul-weather system, without a doubt. This is not always true, as AWD is used to advantage in very high power applications like Porsche's 911TT.
The RWD Mercedes is the best on drive pavement by a mile. The steering feel is the best, and the ability to balance the car through the "twisty bits" makes all the difference. Despite the Subaru having a few more ponies, I could hustle the C230 through the mountains in the summer at a better pace than the Subaru.
This shows the difference in engieering of three companies. Mercedes compromises some winter-safety-for-dummies (people using all-season tires, etc.) for driving pleasure and performance. Subaru installs an expensive AWD system that does a pretty decent job of staying out of your way when not needed (drives better than FWD) but shines in the tough stuff. Mazda goes for cheap. The sticker of the 626 when new was LOW, and the car was built to appeal to a broad audience. FWD is cheaper to build and package. FWD feels "safer" to low-skill drivers.
People thought RWD dead. Ha! BMW and Mercedes stuck to their guns, and are finally being proved right. However, the "masses" are now okay with RWD since MB and BMW added stuff like DSC and ESP to keep low-skilled buffoons from wrapping themselves around poles everytime a skiff of snow fell.
1998 C230 "Black Betty"