Here is a repost of a pm I recently sent to someone with the same question:
50R - Darker module all around. Typically needs run with mids & treble at max settings. Still has a scooped tone all around. Awesome, big, thick, complex distorted tones. Definitely has that 'fuzzy' orange sound, with this one being Slightly 'buzzy'. It has an aggressive nature to it's fuzz/buzz. Again, very chewy, complex distortion - awesome for open chords & very powerful leads. This mod cleans up very well. Has a very spanky, present, grinding type of clean/edge of breakup tone, with a great saggy feel. Much better cleans IMO than the graphic. Sounds very similar to my lead guitarists 1965 bassman head on clean settings. Overdrives very well / takes pedals very well in general.
Graphic - More vintage (less aggressive, less fuzzy/buzzy), brighter in general, not as 'chewy' as the 50R. Also has great, complex distortion, but not as 'deep' in it's complexity. Sounds a lot to me like an old tube rectified JTM on steroids. A lot more variety of tones available with this mod. However, the graphics cleans are both hard to find (gain must be below 9 o'clock) and far less toneful than with the 50R. This is an overdrive mod - not well suited to cleans IMO. But, covers a lot of overdriven tones - from chunky to thin mid gain all the way to modded Plexi/JCM territory and inclusive of that sludge doom tone some folks really dig (not me so much).
So, all in all, here's my take: The 50R is the better choice for cleaner tones and also for heavier tones. The Graphic is better for everything in between. They are both great mods for sure, and I'm happy with both. I'll only keep one, but not sure yet which one.
