07-03-08: TvadIn my case, I think I got lucky--the AT150MLX fed into the Cambridge Audio 640p phono stage is an excellent match, especially at the price. I didn't experience the surface noise problem you did; one thing I noticed is that the 640p drops the surface noise compared to what I was running before.
I agree the AT150MLX is a better value because of the replaceable stylus, as long as one likes the sound as much as the Denon. I gave it a try for this exact reason.
Any chance the extra surface noise you encountered in the AT150MLX vis-a-vis the Benz Micro Ace is a VTA issue? Maybe the arm needs to be lowered a little bit for the AT?