I'm glad i read this thread from 2009, because it's the same issue i'm having in 2019, often with sip box's (ATA's) but also with an asterisk box (freepbx) working as a proxy but suffering less often. And thinking about this also a problem at another site with mikrotik router and asterisk, maybe onc...

Can someone please tell be the real world differences between the rb133 and the rb333?
Will I get higher through put with the rb333?
Does it handle long range better?

Your answers would be much appreciated.