My competition girl is lets just say testing at times, she is stroppy, stubborn, moody, frustrating, tempermental BUT that's only a few days a month and im the exact same so I don't mind! However I find mares are much more loving the geldings they are real triers.
I think with a gelding if you click its nice not exceptional with mares and stallions though it takes much longer so the connection is stronger and more substantial!!
I LOVe them if you can train a stubborn mare your a pretty good rider in my opinion!