To the OP;
1st off let me say welcome to the forum. It is a great place to hang out and read about oil and oil related topics. I have learned a lot since coming here and I actually knew a lot before arriving. Everyone can always learn something new. However, don't come here thinking everything you read will be factual and accurate. Not even close. Lots of agendas and biases here that compromise a lot of what people post. Take a lot of what you read here with a big grain of salt regardless of what product the comment is about. Not everything you read here should be taken at face value.
NOTE - I am a Royal Purple user and I do not try and hide it. I have had nothing but good results with it and I simply relay that. I am not trying to convince you to use RP over brands XYZ nor will I trash those other brands to pump RP up. Just want you to know I actually use it, unlike so many who trash it, and like it. You use what you wish to. I will recommend you try RP in this thread simply because you asked about it specifically
On this site, every few months, there is a new favorite oil/fluid mfg to praise as the end all be all( used to be German Castrol, then it was Penzoil Platinum, now it is Redline ). By the same token you also get the one(s) everyone gangs up on( that has ranged from Royal Purple to Valvoline to Mobil 1 in my time here ). There really are no bad oils out there with the exceptions of some really old stuff or some really cheap stuff like the Accel oil at Wal-Mart that is barely fit for a lawn mower.
As to your question about RP. I have
"personally" run RP in everything from daily drivers( cars, trucks, and SUV's )to muscle cars and hot rods since approx 1990. I have even used it in Motorcycles, outboard motors( 4-stroke ), and yard equipment. It is what I am using in my current vehicle( 2008 Dodge Ram 1500 5.7L = 5W-20 + an RP filter ). It is one of the best products on the market
in my personal experience. Everything they offer( oil, gear lube, tranny fluid, coolant additive, oil filters )has been nothing but top quality for me and returned nothing but the best of results.
On this site it gets beat on pretty bad for some reason. However, if you visit most any automotive forum it is one of the most favored and well reviewed. A LOT of people use RP and love it. Sadly, a lot of new folks that come here and read about it think because this site is an "oil" site that means it is full of nothing but experts. So, all the bashing means it is bad and everything bad said must be true.
Truth be told most here are no different than the posters on the auto forums. Just enthusiasts with an opinion( nothing wrong with that - basically what I am although I try and limit my comments to things I know about and/or have actual experience with ). There are some guys on here who really do know what they are talking about technically( Johnny is one of those as an example )but most are just regular folk like us.
I can tell you that there is at least one poster in this thread bashing RP though that by their own past admissions has never even tried it. I would not be surprised if others fall into the same category. If this thread goes on long enough count on more of those type chiming in with their baseless comments. That happens a LOT here with RP unfortunately and IMO because of that it does not get a fair shake.
Unfortunately, people read those comments and take them as the truth. Now, how much faith can you put in a post bashing a product if the poster has never even tried it? These same folks love to spread outright lies about the product as well such as it is a Grp III based oil, it is owned by this or that company, and just on and on. Nothing but rubbish. It is hard for the new guys to sort through it all. So, as I said above, take what you read with a grain of salt for a while( about ALL mfg's and products not just RP ). After you have been on the site for a while you can pick out the good from the bad.
You will also hear again and again about all the supposedly bad UOA's for RP on this site. Don't believe it. Not true in the least. Another member took the time about a year back or so and brought up all the RP UOA's and they were ooverwhelmingly positive. Couple bad ones but that happens with ANY oil. Always keep in mind that there is no best oil and every application is different. The exact same year engine in 2 seperate vehicles can perform different on the same oil.
As I said, there is no best oil and every application and need is different. Royal Purple may or may not offer what is best for you and your needs. It is however a very good oil and their other fluids are also very good. If you want to use it do so and ignore those who tell you it is no good. That is just untrue. If they used it and it performed poorly for them ok( happens )but that does not mean it will do poorly for you. Mobil 1 has a LOT of complaints of poor performance yet it is probably the top selling oil out there. Mobil 1 has to be doing good for a lot of folks to be #1 even with the price deals at Wal-Mart and the boost it gets from being OEM issue in so many vehciles.
Bottom line is RP is very good oil. So is Redline, so is Amsoil, and Schaeffers, and Kendal, and Penzoil, and on and on for that matter... Chances are you will be just fine using RP if you wish.
I will agree with some who comment on the cost factor. RP oil and their other fluids are generally over priced when you go to most national parts stores that sell it. $9-$10+ a qt for oil, $16-$18 for gear oil, $15 for ATF, etc... is ridiculous. There are lots of sources for RP though where it can be had for the same as or barely over the name brand stuff( Mobil, Penzoil, etc... ). I pay LESS for RP oil qts from my source than Penzoil Platinum sells for in qt bottles at Wal-Mart.
IF you want to try RP just shop for the best price.
Best of luck with your choice. If RP interests you then give it a try. IIt is a great product and far better than so many here try and lead people to believe. Sorry for the lengthy response. Some of these folks get me pretty riled up when they start this.