I have a mare now, and prefer them, i think its because most of the horses we had as a family over the years were mares, we did have a stallion for 7years, who was fab, and some geldings(sons of the mares and stallion, we had-never bought in any geldings).
So have had all of them and love mares best
I'm at a gelding only yard. There are 2 mares who are leftovers from past activities. The YO's little section A ex brood mare is the last one left from her professional breeding days. She gave it all up to work in an office but kept her two favourites and now there's only one left. The other one is an old mare left from when there were mares allowed. She's about to move as her owner is moving away though and I'm not sure the little ex broodmare will be around much longer.
The reason we are geldings only is that the mares and geldings were split into different fields but there were too many geldings (9) and not enough mares. 4 out of 6 mares left (one way or another) in quick succession and all new people expressing an interest had geldings so the YO decided to move that way and have 2 herds of geldings instead.
I have to say the geldings are much better behaved now that there are no mares left to tease them over the fence (the two that are there are on a starvation paddock a fair distance away!)
i have one mare and had a mare before. had a colt and he was nuts. would always say mares but my new loan arrives next week and hes a gelding...so we will see.