I had an RV-6 and an 8" SCT set-up side by side last night. With a bino-viewer the SCT was clearly superior on Mars, but not by much. Earlier in the evening I was splitting double stars and comparing the views. I didn't try for anything very close, but it was interesting to note I couldn't see any more field stars in one scope over the other, and I really tried. It may have been slightly easier to find the faintest stars in the RV-6. The RV-6 was recently recoated and I painted the inside of the tube with flat black paint and applied black felt opposite the focuser.
From my very light polluted backyard in Oakland Ca. I was just able to find M65 and M66 in Leo in the SCT. They eluded me in the RV-6, although I was able to see, just barely, M66 the previous night.
Conclusions? They're both nice scopes. :-)