Yup, the Crossfire is using a recirculating ball type of steering gearbox, but the SLK's also had the same tight turning radius on them, too. Not a noticeable difference, in my opinion.

Basically it comes down to these reasons why I prefer each car:

SLK:
Better interior
Both seats are fully adjustable.
More useable trunk space with the top down.
Better visibility with the top up (rearwards due to MUCH larger window, and to the rear sides).
Engine has more top end due to 4 valve per cylinder design.
Lots more power on the 350, just a bit more power on the 300.
Cup holders that actually hold cups.
Slightly better handling at full tilt on curvy bumpy roads.

Crossfire:
Dirt cheap.
More bottom end torque than 300.
Killer styling.
Better brakes than 300.
Easier to operate stereo.

Well, I can't make it any more simple than this:

If I was forced into paying full MSRP for either of these cars, I would get the SLK300 instead. Since you can get the Crossfire for next to nothing nowadays, there's no reason not to get it instead.

BC.