I'm not sure GMG is a great example since they are used to customers with extremely deep pockets and can easily charge them to fix any issues as part of "regular maintenance". Same with R8 customers for Audi.
I know Endless is a very respectable brake company but I'm also suspicious when they give very little information about their product besides general statements like:
Endless RF-650 can be used in any vehicle, and in any type of brake system.
RF-650 is a brake fluid with advanced moisture resistance properties,
and are not aggressive towards any metal alloys or rubber seals and can
be used by anyone.
All of that is nice but it would be even better if they supported some of that with detailed information like most other reputable companies do with their products. We all know that this type of fluid attracts moisture so what does "advanced moisture resistance properties" actually mean?
I might still give it a try next time I do a fluid flush, lol.