As a man with (very) long hair, I've definitely run across women who despise it and women who love it. My hair goes about half way down my back, but I keep it in a pony tail most of the time, and I think it makes me look more dignified, especially when dressed for a fancy occasion. Sure, some people find it weird, or dated, or hippy-ish, but if you carry yourself with dignity and intelligence, it's hard for anyone to bother about the length of your hair on anything more than a superficial level. I'll readily agree that some men look better with shorter hair, but I don't think I'm one of them.

As a dom, I find having long hair not to have much practical purpose (though for a sub I consider it a must, aesthetically and otherwise), but I think having (well kept) longer hair than my girlfriend is something of a psychological boon, in that it inspires extra effort on her part.