Anyone have opinions or experiences on schilke horns theres one on facebook with a thayer for a not terrible price if its good

I think that's an ST-20. Personally... and I've heard this in a couple other places... the first generation ST-20s are not good. I had a friend with one that was very well made, good fit and finish, valve was quick and quiet, well made slide. It played awfully. No resonance, blow felt strange, just not good.

The second gen ST-21s with axials and Hagmanns are pretty good, but I'd stay away from the 20.