I like to be snug but not tight. I ride in a 14'' right now and I have some room to move but I am not worried about making a mistake and slipping off (My Mom had me in a 16'' for awhile while we where looking for bigger saddle after I outgrew my 13''. I mean...Dang. I was terrified to make a mistake at all because if I didn't move exactly where I should, the horse would have turned and I would have landed flat on my butt. The fact that the seat was slippery did NOT help)
I'm like SH, I like my saddle snug but not too tight..I ride in a 14.5 inch saddle with a high swell. Love it. I really think it also depends on what brand of saddle you get. Some sit and ride bigger than others but feel the same as a small saddle. I have a KO Trading custom barrel saddle and LOVE it.
I have a 14" and a 15" (which my mom swears is actually a 16" so maybe it is?) I actually like my saddles a little bit looser. My 14" always leaves bruises on the insides of my thighs and when I bruise, they stay for weeks, sometimes months. It's not pretty. My 14" is snug and likes to hold me in, but I have a good seat so riding in a 15" (or "16 inch") doesn't really seem to make a difference for me.
I like to be nice and snug. My rope saddle is a 15 inch, and if it was swells, it would be the best thing ever. But, it's a rope saddle and is always pushing me forward, so I'm getting a barrel saddle in a little bit here for breaking colts and barrel racing (duuuur) and it's going to be a 15"
I think it is for sure personal preference and how you are used to riding. Personally I like a snugger fitting saddle for speed events, barrel racing, gaming etc. I ride in a 15" billy cook. They don't have the highest backs on them but their seats are nice and deep with roughout all over to keep you nice and secure.
Although when I rope I prefer to ride in a little bit of a looser saddle, not by much but prefer a 15.5-16" so I have some room to move.
I run in a 15" saddle but the one I am ordering is a 15.5", just cause I want a little bit more room then I have now.
I think it also depends on the horse.
My mare is pretty ruff compared to some other horses I have run, she is a hard runner, so I prefer with her a little extra room to adjust comfortably when I run her.....where as the really smooth runners with really quick turns I prefer more of a snug fit.