I've run both in my ERA. It came with DOT 5, I switched to DOT 3, never really noticed a problem with DOT 5. My concern at the time was that I was running at the track and wanted every "edge" I could get to avoid over heating the brake fluid. DOT3 generally carries a higher temp rating.
It IS a pain to flush the system. I removed the bucket seats, which in itself is not a pleasant task. Then removed the small access panel inside the cockpit to gain easy access to the brakes, again, not pleasant.
Lastly I was VERY VERY careful when adding the new DOT3 because it WILL leave marks on your paint. Even a tiny drop will leave a mark. After I finished and had spilt a tiny bit near the brake reservoir container I flushed that area with water. To my horror I found out within a day or two splashing water from the hose caused a bit of brake fluid to fly out and onto the fender area. Sure enough, left a few tiny white spots on the fender. They won't buff out. I all ready got plenty "road rash" and such, so I shrugged it off.
BUT, what if I had a really nice high dollar show quality paint job? Devastating! You could make a case for DOT 5 all right!
Sounds like your calipers need maintenance, and I'll BET that little more than a good total FLUSH and BLEED will make a world of difference in how they feel! Just be extra careful if your using DOT 3 to do that!
