I have been using dot 5 silicone brake fluid in 5 cars Ive built all using wilwood master cylinders and slave cylinders and have never had a problem with any of them. I use it to keep the dot 3 off my paint, also used it in a 48 Lincoln convertible coupe for the power windows and top and have never had a problem. I would say use it and dont worry. until one of my cars fails from using it instead of dot 3 I will keep using it.
I was told that it is more prone to leaks and absorbs water. I guess you have to look at the pro. If the master cylinder goes south it wont strip the paint inside your car. My 66 belvedere is a rust free Tx car but the master cylinder leaked down the inside of the firewall. It then wicked the entire inside of the car. No rust other than surface rust but it will need bead blasted.
"The only major user of silicone is the US Army. It has recently asked the SAE about a procedure for converting from silicon back to DOT 3-4. If they ever decide to switch, silicone brake fluid will go the way of leaded gas."