Yes, I own one. Also a R3S.
It is a good mouthpiece, but I couldn't get used to the rim profile. It was too round for me so my endurance would suffer from it really quickly. My girlfriend tried it out and she actually uses it as her go-to mouthpiece. I find their concept about combining different cup shapes very interesting though, and indeed, the actual cup shape of the mouthpiece is unlike anything else. They also have a HUGE backbore and that's something you really notice!
While a bit on the expensive side (I paid 180 euros for a gold-plated brass mouthpiece buying directly from Patrik a couple of years ago) Randefalk also offers different sizes rim shapes and materials for their mouthpieces.
Last edited by Vito; 02-11-2021 at 03:26 PM.
Reason: Typo
Music educator - Brass Instruments Enthusiast - Euphonium Player
2019 Besson Sovereign 967T-2 - Alliance DC3