Any truth to my feeling that MM carts are possibly better than MC on rock recordings?

I think this is just a quirk of the Ortofon MC line. Some 12 years ago when I "upgraded" from Ortofon Kontrapunkt "c" (Cadenza Bronze) to Jubliee (Cadenza Black), I definitely did not feel as engaged in the music - and yes, rock music fell flat. Then I upgraded to Windfeld MC and it helped but did not mitigate all my issues - the lower Kontrapunkt "c" was a better all genre listen. That Jubilee uses a Shibata like your Quintet Black, btw. I definitely stayed away from the Cadenza Black (Shibata) because of my past experience here.

But that is NOT at all representative of MCs!! I now have many other MCs (Koetsu, Shelter, Benz) which all sound beautiful and satisfy completely with rock and heavy metal. I borrowed a VanDenHul Colibri XGW and that was great too. I even now have a higher-end Ortofon that I love too: the A90.

To be fair also, part of the problem back then was certainly in my phono stage. As you move up in the Ortofon MC line, the output level also tends to go down, and going from a heathy 0.4mV output to 0.26 can be trouble if your MC phono stage or SUT is not well suited to that. My old phono stage back then (Sonic Frontiers Phono 1) definitely lost punch and dynamics below 0.4mV.

Not for me.

I had one of the best MM cartridges in an Ortofon 2M Black.  Sounded very good compared to other MM cartridges I had but compared to my LOMCs the black was left in the dust for all music but especially rock.  It lacked dynamics, sounded clear but anemic and was unrefined compared to my MCs which added more distortion to compressed rock recordings. 

The best MC i had for rock was the Audio Technica ART9 which had amazing bass, a huge sound stage and explosive dynamics.  

@mulveling , My experience pretty much mirrors yours. rauliruegas is right about phono stages. I think there are stages that sing with moving magnet cartridges but do not do so well with MC and vise versa. But, it takes a great moving coil to match the rock performance I get out of my old AR PH3 SE and the Clearaudio Charsima. I have yet to here a MC top that level of punch. No, the high end does not quite have the air of a good MC but the bass more than makes up for it. The Soundsmith Voice almost displays the same dynamic but sounds more like a MC cartridge. High output cartridges with top stylus/cantilever assemblies can do an amazing job considering the low price. The Goldring 1042 has got to be the best cartridge for the money made. I am about to order a Channel D Seta L Transimpedance phono stage in red powder coat. Galen Carol has ordered me an Atlas Lambda SL. God knows when it will show up. The combination has a reputation for being extremely dynamic and I am hoping this gets me past the Charisma for dynamics with all the magic the cartridge is known for. It is a sure bet for 20 large. There is no way in h-ll that this is going to be16 large better. Aren't there much more important things to spend that money on? Second thoughts?  The problem with ordering items that are not going to show up for 6 months is the 6 months you have to argue with yourself.

The best cartridge for rock will also be the best cartridge for classical. It can be no other way.