There's nothing specifically wrong with the SLK as long as you can fit into it to drive it. They were designed for women. I'm 6'1" and can barely shoe horn myself into one.

The only specific achilles heel that I'm aware of with them is the door panels. They peel and come apart. There is an update for them.

I can't imagine buying an SL or SLK with an automatic transmission though. Buying a sports car with an automatic transmission is like hiring a prostitute that doesn't have the necessary equipment between her legs. What's the point?