Which cantilever to choose for re-tip


I have two cartridges I plan on having re tipped by Soundsmith. One is a Shelter 501 II, and the other is a Lyra Lydian B.
Both of these came originally with boron cantilevers. 
Is it worth the $450 each for the boron or should I go for the $350 ruby? 
jsbail
Ok. Seems boron is the way to go on the Shelter. More than half what I paid for the cartridge but still seems worth it if it sounds great when repaired.
I decided to have them evaluate the Lyra. The stylus looks fine but has turned sideways. The cantilever is loose. I hope they can glue it.


FWIW, I chose boron for my Benz Ebony LO, which is what it came with, and I'm very pleased. Sounds like stock, which is what I wanted.
I can't swear to this, but I do believe the Mk3 was at most only a few hundred bucks more than the Mk2 (not double the price of a Mk2), last spring when I was in Tokyo.  It may even have been the same price.  I eventually bought a Mk2 Mono.
 It turns out the Shelter could not be repaired do to suspension damage. My fiancé was trying to do me a favor by dusting. Married her anyway.

Going with a boron cantilever on the Lyra.