I flushed my system with OEM dot 5. With the car sitting idle 75% of the time I thought it best to get away from the moisture issues with dot 3 and dot 4 fluids, in spite of never having trouble with them.
Some claim they have trouble bleeding (I didn’t) and the result is a mushy pedal (don’t think that will be an issue with power brakes).
I know people that swear by it and others that won’t go near it. Guess I’ll form my own opinion over time!