I just did an oil change with O'Reilly 10w30 conventional and a quart of Rislone, at 150K. When I had the valve covers off on my Jeep Grand Cherokee 5.2, there was a small amount of carbon build up on one side of the head that I was able to scrape and vacuum out. The previous owner had been driving it around with a bad radiator cap, so the upper hose wasn't getting pressurized. I also replaced the PCV valve. Those factors may have had something to do with adding to the small amount of normal carbon build up engines accumulate over time.
My original plan was to use BG Quick Clean with the above house brand oil and a new filter, and to do a second rinse with another 5 quarts of fresh oil. I had second thoughts after concern over something getting dislodged during the cleaning process, although it seems there are mixed opinions about quick flushes. After starting my vehicle with the new oil and Rislone in, it was noticeably quieter as the rockers and lifters didn't nearly make as much noise. I can't attribute this to Rislone, as I replaced a cheap MicroGuard filter with a Bosch filter. It is a possibility, however. Also, my oil pressure looks to have dropped a few PSI with Rislone in. I'll update this thread with any progress.