The Ortofon RS-309D is a very good tonearm. That being said I just upgraded to an Ikeda IT 407 CR1. It was a distinct upgrade from the Ortofon. Currently using it on my Garrard 301 in a Woodsong plinth with an Ikeda cartridge.
I have not owned a Triplaner tonearm so I can't help with any thoughts on that.
I have not owned a Triplaner tonearm so I can't help with any thoughts on that.