After moving, I set up my stereo, removed my MMC4 from its box, and replaced it on the tone arm of my Beogram RX.  I adjusted the counterweight to what seemed right, but didn't bother to recalibrate and check everything before trying to play a record.  That was a mistake.  The tone arm skidded off of the record onto the aluminum, and once I had adjusted it properly, it was sickeningly distorted.  I found Soundsmith's website, and followed their instructions to visually inspect, and though I saw nothing out of place, when I tried the cartridge again, it didn't even play distorted- just a hum.

I have tried a lot of B&O cartridges in my time and the ranges have always had a hierarchy with a basic model and ever increasingly expensive models above. In the days of B&O making their own, the price differences were actually not that great and I often had the full model range. I do have a Soundsmith cartridge - a SMMC20EN, which is the equivalent of the SMMC3 in many ways. Excellent cartridge but I bought it to help out another member who needed to sell it. If I was buying for an RX deck, I would get a SMMC4 of which I have heard nothing but praise. I have had MMC3 and MMC4 cartridges and have done A/B tests and didn't notice any big differences.

If you have been happy with MMC4 then you will find that SMMC4 is a distinct inprovement in solidity of bass and sweetness of treble. My advice is to save the $80

Thanks very much for the advice!  It's what I was hoping to hear.  Now off to Soundsmith to place an order.