I just got a Duo-R from him and am not happy with it.
My CD drive wasn't working, I had to open it up and fix it myself. The RGB mod doesn't look the greatest, it's too bright and there's a slight shimmering in all four corners. Most annoyingly it intermittently makes my TV flick between 4:3 and 16:9 modes, pretty much makes playing in RGB impossible for me now. Also, it looks like crap when ran through a component encoder.
I'd never buy from him again nor would I recommend him to anyone.
I could have bought a boxed and complete Duo-R from Hit-Japan in nicer condition and had it RGB modded by someone locally for cheaper than what doujindance charges for a loose system plus shipping.