Cartridge Selection

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. 

gareents-
I've heard most of the carts mentioned on a VPI. Great suggestions.

Include the Audio Technica ART9 in your search. I had one on  my VPI. A Kiseki Blue replaced it,only because of a crashed cantilever.

Like everything audio, it subjective like choosing your favorite ice cream.

A couple years ago, here on Agon it was the "flavor of the month" for a reason. At $1K, it performs above its price point. Check the archives.

The SS models are especially attractive because of reasonable repair cost. Most who own a high end cart, eventually experience the trauma of a cantilever disaster.

Also,if you haven't already, consider trying a tube phono to really hear whatever cart you choose. Again subjective, most opinions seem to agree a tube phono adds a level of "real" that is more convincing than SS.

I don't want to hijack the thread, I do not have a VPI but wanted to comment on the sound of cartridges.  

@mijosten you have a lot of experience with analog, I would however offer a different option about one analogy you made - in my system I would characterize Transfiguration to sound more like SS and Ortofon I would agree with you - in the middle.

@GAR Ortofon for me is hard to beat, extensive line, good sound with options, and a long tradition of making cartridges.  I am using my Jubilee now as I try to figure out what's wrong with my Transfiguration Proteus and is it fixable.  Another example of why I will always buy from a company likely to be in business  for the long haul, especially if I spend large like I did on the Proteus. 

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