Yeah, I had a Model R...serial #2 in fact. Don't know how much they changed over time, but mine was a bit dark, though through my Marshall 20 watt, it sounded pretty great. Closer to a DRD but more open/less compressed. I really liked the resonance control. You can get some nice feedback at lower volumes.
Cool, now classic Bjorn vids...(why isn't there a "Bjornberry Overdrive":laughing7 )...B Dizzle's demo hear gives you a good idea of what it's capable of:
http://www.youtube.com/watch?v=1GA_W4F7Kwo