Be aware that some phono stage MM inputs are too low in gain to even properly accept some HO MC cartridges. I have talked to some people recently that had 2.0mv output MC carts, and the output was insufficient to get decent volume levels. Check with the maker of your phono stage.
Best High Output MC
It seems like it's getting really hard these days to find a preamp with a decent phono stage for even medium output MC even among the very top end preamps. Given this fact, a high output MC or MM seems like the reality for me if I want to upgrade my preamp but keep a good phono stage. What do you think are the best of the high outputs or MM's or is it better to look for a separate phono preamp to accomodate my MC?