I have a pair of the RS460's - love em... same as the Scubapro MK16/R390 setup, so, anyone that knows how to service either brand can help you... both breathe exceptionally well, the diver adjustment really makes a huge difference...
I've been a big fan of TUSA though - commitment to quality and used their RS130 regs when in training - had an awesome experience with them too... no qualms anywhere... nothing against the other brands, I just know I've been consistently happy with my Tusa stuff...
(it scored pretty well on the Scubalab tests as well)
http://www.scubadiving.com/gear/regu...breathers_2005