Brake fluid

Sorry if I am hijacking this thread and I do not mean to but I have a question regarding brake fluid. Is there any difference in brake fluids in regards to heat generated by the braking system? My car does not have any brake fluid leaking but I notice if I take the car on a long trip that when I get back I notice that sometimes it almost seems as though the brake fluid is evaporating or maybe burning off? because my Master Cylinder is down a little on the front fluid side. The lines and Master and rotors and pads drums and rear wheel cylinders are all recently replaced and like I said there appears to be no leaking when the car is parked. Is there any brake fluid that stands up better under high temperatures? Dot 3, 4, 5, 5.1??????