Does hearing the best in high end audio make your opinions more valid?

No.

Not necessarily. If it did matter, anyone could win any argument simply by claiming he’s heard the best of high end equipment. At its core it’s really a logical fallacy. Case in point, go to a big audio show sometime and you can observe just how difficult it is to get great sound out of the best of high end equipment, including speakers and cables.

The more and varied the systems you have exposure to will help a you figure out what your preferences are.  Which, if well articulated, could help someone else to some small effect.

"The best" is a concept that I don't think we will ever reach agreement upon.

+1 for onhwy61

It does if you have a good perspective it helps you understand different  sounding high end set ups.You can compare them and get a sound perspective if you know what to listen for.Enjoy!!