For those interested I can perhaps chip in with some recent experience
Last weekend I sat in on an Ortofon demo. 2M red, blue, black, Quintet black, Cadenza bronze & black.
All were mounted in detachable headshells. The system, top end Project TT with Musical Fidelity mid-range solid state and Klipsch speakers, with the exception of the addition of Ortofon's entry step up for the MC's the system remained unchanged.
2M red offered decent engaging sound. Someone earlier in thread mentioned they found using a cheap cart on better table offered better sound than a better cart on a more basic TT. Based on this demo I can understand that comment.
Quiet a change moving on to the blue, far more detailed by comparison, the red while engaging didn't allow the same level tone and insight into the way an instrument was being played. It sounding sweeter with incidental instruments more obvious in the mix. Vocals however were noticeably more sibilant, for me it tipped the balance toward overly so though others didn't feel it was a problem. The black alleviated the sibilant issues while extending the sense of real instruments being played. Soundstage was set between the speakers and there was nice tone and flow to the music, very acceptable sound but for me missing the beauty of what's available in a really good analogue set up.
The Ortofon rep clearly stated that the red/blue stylus were interchangeable as are bronze/black, while it may fit adding a bronze/black stylus to a red/blue body does not get you a bronze/black sound, just something different.
Moving on to MC the really significant change was the way in which the soundstage opened out, there were significantly more ambient queues that defined instruments in space across a wider, deeper stage, while retaining all the tone, body and flow of the MM range. Much more to my taste though I can understand some may favour the different flavour of the 2M black presentation
