The only 'good way on oil' is by doing oil samples. I have been doing
'engine' oil samples for over 20 years. Quality oils have been changed
many times over the years. Be aware that USA brand Oils are giving us
a 'lot of smoke'. Just saying about Oils.
You can learn a lot about whether the oil is truly a full synthetic on a Type IV base stock, or whether it is a "full synthetic" meaning a highly refined mineral oil Type III stock, from the oil's Safety Data Sheet (SDS). It doesn't give you the exact answers but hints at these things in Section III of the SDS. There's quite a long discussion on this topic on several General Discussion forum threads.
To summarize, the new XPS Fully Synthetic oil, like most fully synthetic oils, is a highly refined mineral oil based on a Type III stock. However, like most similar name brand oils, this is not necessarily bad and to be avoided. To claim fully synthetic it must largely perform as per an ester based actually synthetic oil. It has additives which help it do so too. This same wishy washy claim to be "fully synthetic" follows the same marketing rules in many countries such as Canada and the UK. It still doesn't make these highly refined mineral oils bad oils though. If they meet all the industry specifications they will provide more than adequate shear protection up to the 9300 mile BRP oil change intervals. However, I change mine at 5,000 miles to be doubly sure. Oil change analysis done by BajaRon on reports on his, and his customer's, bikes has proven this to be more than acceptable oil change mileage.
I've attached the SDS sheet for the new XPS Fully Synthetic oil and my determination of its type from Section 3. If you Google Oil Safety Sheet Oil Type it will tell you how to read between the lines on what the oil is actually based on, type of stock wise.
So, most name brand fully synthetic oils are often the same, even fancy name brand stuff you can trust, from around the globe.
Having done oil sampling in the past, in the last ten years I've stopped bothering as changing the oil every 5,000 miles for the manufacturer required oil brand, weight and specifications, has led me to no longer worry about things if the engine is performing well and making no weird noises. Having got silly high mileages out of various Jaguar Land Rover engines that everyone assured me would have all kinds of mechanical issues one day outside of warranty, I just stopped bothering with modern motorcycles and my Spyders.
After time after time oil analysis reports coming back with essentially the same data corrected for normal mileage related values, I just trust the oil itself now. Nowadays I would only do the oil analysis if I was suspicious that something was not quite as it should be.