Ok; after a night of REALLY playing the piece (the other night was just a brief first impression), I'll do an actual review, and then I promise I'll stop spamming this thread.
Tone
Thick is way I described it when I first tried it, and I still would describe it that way. That being said, I can brighten up this mouthpiece quite a bit if need be, but I don't feel like it gets harsh bright. Although the sound is dark naturally, it's compact, and doesn't get too spread. I'd describe it as a medium focused, complex sound. The palm keys really sing on this piece, and remain thick and complex. The altissimo pops out pretty easily, although I'm still gettting used to where it sits. One thing I noticed while recording is how clean/pure the altissimo notes sound.
Response
This mouthpiece responds well, but I found myself having to be very centered had to be careful not to get too tight with my lower jaw. The more I get used to this piece, the better the response is, but (like a link) there's not a whole lot of margin for error. Last time I saw Ed Calle playing, he was playing a Link. When asked why, he said it was because he wanted to get his embochure centered, and Links force you to do that. I felt that way with this piece. There's a pretty big range of timbres that you can get with this piece, but you have to learn where they sit.
Volume
Two days ago, I would have said that this is a piece for quiet playing only. Today, at the end of playing for a few hours, I can get about three times louder than I could the other day. I imagine that this trend would continue as I get used to the piece. When it gets loud, it stays fat and thick. That's something that you lose with a piece that's easy to play loudly.
Construction
Not much to say here...it's visually impeccable. No built in bite plate, just a mouthpiece patch. I wear through a built-in plate way too quick without a patch anyway, so this doesn't bother me.
Overall
Back in the day, I was a bright mouthpiece guy. I worked on cruise ships playing loud music, and I had a Guardala Studio and a Ponzol M2 that were my main pieces. These days, I'm an HR mouthpiece guy all the way. Now that I play gigs that are mic'd a little better, I've felt that I can get a better, more complex sound from them. I've been playing Phil's pieces for a couple of years now, and have always liked them a lot.
Now I work in a shop that carries Phil's and Theo's pieces, as well as many others. *disclaimer....while I sell their pieces a lot, I'm not commissioned in any way for them; I just like them, and enjoy recommending them. I sell (and like) lots of other maker's pieces too*
All of that being said...Phil's/Theo's Tribute is an incredible, complex sounding mouthpiece. I feel if I spent some more serious time with it, it could quickly become my favorite metal mouthpiece, if it's not already. If I was a little less broke, I'd be buying the one I have now.
Here's one more clip without effects from this evening. Even if you don't enjoy my playing, you can enjoy my dog quietly serenading you in the background from two rooms away.
(I'd watch in HD, as YouTube seems to compress the audio for anything below 720p)