I have had both and out of all the horses I've owned, the most dependable have been my mares. Of course, Frosty, then Hannah, and also young Farrah, and we also owned a gorgeous Arab mare for a time that was what I would call bombproof. If a mare is witchy in heat she doesn't stay around here long...I expect them to act the same whether they're in heat or not. I have also found my mares to be less spooky. I have no idea why that is! I am looking at another mare on Saturday!