Cartridge Selection

The Koetsu is way too stiff for that arm.The Lyra Delos is perfect as is the Clearaudio Talisman Gold. The Clearaudio is a bit more dynamic and it is also brighter. If you think you need a little more treble it is perfect. If your system treble is right I would go with the Lyra. I am a big fan of Ortofon cartridges but at this price point I think these two are a better value  price to performance. Up a little higher the Winfeld Ti takes over until you get to the megabuck cartridges. The best arm I know of for Koetsus is the 4 point 14. You need a heavier arm. The Stone bodied versions will go in a slightly lighter arm but they are very expensive. Never use a uni pivot  with a Koetsu. Moving iron cartridges can sound great but they are very sensitive to magnetic fields. DC motors generally work fine but if an AC 
motor is not well shielded you are going to get a hum which gets worse as the cartridge gets closer to the motor. Unless you have used one before and know you won't have a problem I would avoid them if you have AC motor. Cartridges are like ski boots once you use them there is no turning back.

I have a friend who put a Soundsmith, not sure which one on an old Thorens TD 125 and it hummed like crazy not to mention that the arm was too heavy for it. He returned to an Ortofon SPU. 
Different cartridges have different sounds so you have to know what you like. I could give a hoot about stylus replacement. I have never replaced a stylus as I always want to try the next best thing. The single most important spec is the cartridges tracking ability next is the compliance. The biggest mistake you can make is getting a cartridge that is too soft for your arm as it is hard to make an arm much lighter. Too stiff and you can always add some weight. I always shoot for vertical and lateral resonance between 8 and 10. I think you get the best bass and dynamics here. I have never seen record warps go up that high.
Cartridges are like Tube VS SS electronics. Koetsus are decidedly on the Tube end of the Spectrum as are Airtight and the now defunct Transfiguration. Ortofons and Clearaudios lean SS. Grados and Lyras in the middle. I have not hear an Epoch yet. I have never had a Soundsmith or any other cartridge I have not mentioned in my system so I can not comment. With a SS phono amp I  like Grados (which can track anything) and Lyras. With tube phone amps I like Ortofons and Clearaudios. Currently I use a Clearaudio Da Vinci with and ARC phonoamp. Fabulous combination. I have a Koetsu Rosewood Signature Platinum, an Airtight Supreme and an Ortofon Windfeld Ti in reserve. The Windfeld Ti is also a cartridge that can track anything. It is a great cartridge for Rock. I have my eyes on a Lyra Atlas low output. I had a friend's in my system and it was wonderful. My audio savings account isn't up to it yet. 

It wasn't Transfiguration's fault that it's owner and principle brain trust passed away. Unfortunately, he must not have had a relative interested in carrying on like Grado and Koetsu. The Proteus was a great cartridge. I never owned one but I had it in my system for a weekend. We have a group of diehard vinyl audiophiles who all trust each other and we swap cartridges all the time.  If you can't get the Transfiguration fixed MySonicLabs is supposed to be very similar. One is probably in my future but the Atlas is first. I would also love to get a second TT so I can AB cartridges without having to fiddle around. Got to have something to day dream about. I'm not sure pops but I think Van den Hul will repair cartridges. 

Tablejockey, I think that is particularly true at the less expensive end of the market but when you get to Sutherland and Pass SS phono amps that argument breaks down. The one gig I would love to try is Channel D's system where you have an unequalized Phono amp go to an ADC and let a computer do the equalization. Interesting concept but I would have a hard time spending money on it. I myself tend to lean toward tube phono amps having a weakness for ARC products and 6922s