You are asking in the appropriate place. I am interested too. I will say that I believe most owners keep the M3 incandescent, me included. I believe the Malkoff MD10 was popular before they were discontinued a short while ago. Best.
While I cant speak for the whole of folks owning a light with a Z46/M3 head I would have to say it boils down to beam profile with LED towers designed in this application. I own several MD10's and in fact have custom built several myself. They all suffer the same issue. A very narrow beam profile. Not without some spill but definitely a throwy son of a gun. All the while the MN10 and 11 being more suited for a broader beam projection. Color can be an issue too. Depending on what tint LED is used. I know I had to settle for LED's below 4500k to get rid of any hint of blue.
Ooops! Forgot to comment on the OP info request. I don't own one of Mark's LED towers but I have owned (and still do) many of LF products and they are top notch. I am more than sure he took the time to design a quality tower and AFAIK his are the only ones built offering multi modes at this time.