Mudman-
Your pocketbook might steer you away from it!!

DOT 3, 4, & 5.1 are all glycol-based & compatible with each other, with each one having a successively higher boiling point. DOT 5.1 doesn’t hurt, but it doesn’t help unless you generate extremely high heat from racing & VERY hard braking. They will all damage paint & absorb water.
DOT 5 is silicon based & more stable but CANNOT be mixed with the other DOTs or it turns into globs of silicon in the caliper pistons, just like what you caulk your tub with. Being it doesn't absorb water, raw water is bouncing around the calipers causing corrosion & wreaking hovac, an issue you don't have with the other DOTs. It's also absorbs & holds air making it harder to bleed the brakes, especially if you pump the brakes too fast and aerate the fluid while bleeding them. Silicon compresses more and causes spongy brake pedals & levers.

I run both DOT 4 & 5 in various bikes and according to the Service Manuals DOT 4 needs changing every 2 years while DOT 5 needs changing every 5,000 miles.

IMO, the only advantage of DOT 5 is that it won't hurt the paint when you spill it on your bike, due to it being silicon based.
Hope this helps.