I'm in the market for my first ever horse (!!) and I like a few that are 16 or 17hh. I measure up at exactly 5' 4.5" and since I'm 28 I don't think I'll be getting any taller. I know that it's important to not get a horse that is too short for you, but are there any downsides to getting a big guy? Besides the extra effort of getting on, obviously.
You fall further, its harder to get their bridle on if they decide to stick their head in the air (been there, luckily I have a magic technique), you need a bigger horsebox for the big ones, you need bigger rugs, headcollars etc (which cost more, here at least), they eat more, they need more space, most take BIG steps (for shorties like me), when they get muddy you've got a whole lot of horse to wash (lol), bigger shoes cost more money...that's all I can think of at the moment.
If it becomes a problem, its a BIIGG problem xD
Those are just general things, like I know big horses with quite short strides, generally in my experience. I had to walk a 17.2 the other day, he was walking really slow for him but I had to like float walk to keep up and he was like giving me a weird look like, "keep up leprechaun!" and the guy behind me was laughing cause he's taller and he has no problem walking the horse with his big long legs lol.
Those would not be significantly more than say a 15 something hands but if I compare a big horse to my wee Harry at 13.2hands its a decent difference.
A woman at my yard is 5ft 3 and has a 17.3 irish draught.