I don't understand how women are so willing to call mares crazy during their heat, but when talking about themselves are ready to get offended at such stereotypes.
I have one gelding, and five mares. Yes, I know when they come into heat, they don't hide it, all of mine are very obvious. But they don't give me any more grief than any other horse. It depends on the mare, truly, and their training. My mares are good, but they certainly aren't the best they could be, but even then I don't have any more problem with them in heat then I do out. I wouldn't let being a mare be a deal breaker. I've met a few in my life that are horrors when in heat, but then again my gelding can be terrible to ride around mares simply because he prances around and moves 'prettily' but uncomfortably. They don't even have to be in heat, that's just how he is.
If I get another horse, it will be a mare, along with 80% of horses after that. If you find a good one, go for it.