I shelled out the bucks for a Schilke P5-4 a few years back...I love that horn. I should also mention that I bought the MA conversion (haven't really ever needed to use the extra slide for the 4th valve). If I was buying now, I'd either get the standard version or the Butler/Geuyer conversion. As for mouthpieces...for me (and this may/will be different for everyone), I've found that a bigger mouthpiece that allows for more air into the horn is the way to go. I have a Monette Prana AP-5L that's shallow so it's easy to play something like the Brandenburg 2, but for nearly everything else, I get too thin of a sound. I tried out a deeper cup and bigger bore mouthpiece and the difference was amazing. Still had range, but the sound was so much more full. Try everything out and buy what feels best for you.