I have never used Royal Purple, but a small engine, (or most any other engine) will RUN the same on any oil you put in it! Especially if it the proper viscosity. I personally think this Idea that "my engine runs better with one oil than another" is just silly. Just my personal feelings, as I have used everything from Amzoil to Supertech, and never seen, felt, or heard any difference.
I've run it in my Toro Recycler for the past few years. My local True Value sells it for around $8. Runs fine. Does it run any better? Who knows? A quart of it is relatively cheap and it makes me feel good to run synthetic in my OPE.
Rotella in a 15W-40 or a 5W-40 will be thicker at operating temp ... and be quieter. Oils with a fair dose of moly also tend to run quieter. Quieter is not always better.
I would assume this is just their 10W-30 oil in a different packaging. Too many people with the idea out there that you MUST run SAE30 in OPE. Period. Easier to change packaging than a few generations of backward thinking.
You could run that. Would be fine. What temps are you running at? GC might be the best for your application. Others here have ran it and have had good results. My John Deere LX289 lawnmower is liquid cooled and it has Royal Purple API licensed 5w-30 in it. No problems at all. Oil temps are around 180*. Next oil change is going to get GC.....