I have a Soundsmith SMMC-2 on my TX-2. My TX-2 with the MMC-5 I had on it sounded much brighter and "livelier" than my old 3404 with an MMC-20EN. The Soundsmith cart now has about 60 or 70 hours on it. It definitely picks up even more high frequency detail than the MMC-5 did. On some recordings I feel like there is a distinct lack of upper bass/lower midrange. The frequencies that give pianos, acoustic guitars, and some vocals their body sometimes seem to be rather attenuated. On other recordings it's all there in spades. The bass/mids are stronger than when the cart was new, I believe (and I taped some tracks as soon as I got the cart to have an objective reference).
I think I'd still like the cartridge to have more midrange "beef" than it has, but I'm not sure if it is the cart, the table (I have another table - an RX - to try the cartridge on), or the overall system synergy. I'll have new (to me) speakers tomorrow, so that's another change to check out.
Overall I'm very pleased with the cartridge but not yet ecstatic. Some things it does extremely well, and on some LPs it does everything extremely well.