Hi Eddy,
I'm not sure what the reviews are on about with the auto, it is all Merc gear and well proven. I have the auto and it is super smooth, it adapts to your driving style, so bear that in mind when test driving as depends how it has been driven will affect how it drives when you test it.

I have the convertible ( my first ) and so far no problems, it is relatively quiet with a taut top. Mine is an '05 with 52k on the clock and kept outside with no cover used daily.

Good hunting !