The mechanics at a former power plant I worked at swore by RP. Used it in the boiler feed pumps. I do recall making rounds one shift & noticed a mechanical seal failed on the outboard side of a boiler feed pump. Went back to the control room and swapped feed pumps before the in service unit completely failed. Once I swapped pumps & placed a clearance on the one with the failed mechanical seal I noticed the oil reservoir was at least 90% water. I was surprised when it was torn apart the outboard bearing was still in good condition.
I'm not saying it would have lasted like that for long but figured with a 90/10 water/oil mixture in the oil reservoir that bearing would have been toast. It's also very possible that mechanical seal had let go just prior to me walking out to start my rounds on the unit.
Besides that facility, I've never used RP products in any of my equipment