Let's Say A Guy Wanted To Chose Between A Koetsu Jade and

Blue Lace is the most dynamic Koetsu but still sweet as hell, Jade is warmer - warm even for a Koetsu. My preference has been Blue Lace from hour #1 but both are undeniably Koetsu sound.

All Jades and Blue Laces have Platinum magnets, as far as I know. Onyx is the older model that has some non-Platinum magnet versions floating out there. I have an Onyx with Platinum (early P - #P022!), and one without (Musashino Labs), both rebuilt to 2018 Koetsu spec. Yes, the difference is quite significant. There is a reason they moved to Platinum magnets (from samarium cobalt?) for their modern motors in stone bodies lol. It has more of the creamy, sweet sound you'd expect from Koetsu thanks to the platinum magnet, but better clarity, bass and dynamics from the stone body and new motor spec. 

@lewm 

I've never heard of a non-Platinum Jade, yet. Doesn't mean it doesn't exist, of course. Onyx and Rosewood are the models which have been available with different magnets over the years. The older "long body" models (Rosewood and Onyx) are alnico, because it was physically a very long magnet cylinder compared to the compact samarium-cobalt and platinum.

With the exception of Onyx, I believe all stones (Onyx was first, then Jade, then everything else) can be assumed to have platinum magnets. A top-plate serial # beginning with P (e.g. P022) always indicates the platinum magnet. I sometimes see old Onyx short bodies for sale (gold pins is the clue), where the seller clearly has no clue what they actually are but listed as "Onyx Platinum" when they're almost certainly not.

@rauliruegas Jade and Coralstone are both on the warm side here. I ended up preferring the more dynamic, detailed, "sparkly" Blue Lace. Onyx and RSP are in the middle. I like those too. 

Yes, in fact, this year I have been exploring and enjoying more detail-oriented and "bright" cartridges like AirTight PC-7 and Shelter 7000. But Windfeld Ti still doesn't do it for me (midrange). No need to denigrate Koetsu; in some system iterations they were the only cartridge that sounded "right"!