Brake fluid type is a bit like discussion religion. Its still a hot debate over what to use. In my experience for cars like ours which do not see daily use, DOT5 silicone fluid has significant benefits. It is essential to clean out the system entirely, and then install the DOT5 fluid properly. The common complaint is the DOT5 made my brakes spongy. That’s usually because it was applied incorrectly with a vacuum pump. We all know that DOT3 fluid is hydroscopic (absorbs water, which causes rust and corrosion). Well DOT5 is hygroscopic, it will absorb air. It must always be pushed through the system with pressure from the reservoir and the bottle should be fresh and never shaken. The other nice thing is that DOT5 will not eat paint if spilled accidentally.
Here is another thread on the subject, with testimony from Tiger Tom:
I’ve taken additional steps to insure all the air is out of mine, and my Alpine has a solid pedal with DOT5.
Here’s a demonstration of all the air being boiled out of a sample of silicone brake fluid.