It really depends on the sounds.
I've got sets of 14s that hit the sounds I'm looking for perfectly.
I've got sets of 15s that do the same.
Heck, the Paiste PSTX Swiss hats only sound right to my ears in the 16 size for one setup and the 10 size for the other. I'm running the 16s quite effectively in that setup. The 10s are a hoot with that quick snap setup.
I don't believe I have a generalized preference.
I'm definitely in the "whatever is needed for the job" group.
when I started coming to this forum I thought...why on earth would anyone need 15" hats. No I own a few and a set of 16s.
I play a lot of closed hat and like when doing two handed stuff on the hats for them to be in two different areas for different tones...15s are great for that. 14s are like a great commuter vehicle...15s are a little more luxurious...13s more like sports cars. I'm having trouble finding a reason to keep my 13s
I love both. Maybe it’s just the specific ones I have, but I do feel like the 14s are quicker. I am into low pitched hats though, so obviously increasing diameter can do that. So my bag right now, for the one band I’m in, is lower pitched 14s. But at home I prefer paper thin 15s.
I like 14's best for everything I care to play. I sold the 15's I had for a couple of years. They weren't horrible at all, but actually sounded good - they didn't feel as good to me as my 14's though. Maybe it's in my mind. I don't care for 13's at all.
My first hats were 15" New Beats. Played them from 1977 to 1999 (not continuosly but...).
1999 I bought a set of Quick Beats because...welll....
*everybody* plays 14" right?
First thing I noticed was I had to keep my eyes on the 14s because from so many years playing 15s I was missing the edge at times. Sometimes even dropping the stick because of the miss. But they were quicker and crispier. Tried and still have 13" K\Zs, plus 14" new New Beats.
Latest experiment has been using 16" IAK dark crash over a very old 16" A. Almost perfect size and profile match and a very cool sound.
Put me in the camp of using whatever works!
Sometimes it is plain old boredom that necessitates change. If so-I'm covered!
I have never put a stick on a 15” pair in my life. I have always preferred brighter and quicker hats. I subscribed to the idea to use smaller and thinner hats (13 and 14s) since I play mostly on the light side and lower volume side. I always equated bigger with louder and just kept away from 15s for that reason, though that isn’t always necessarily true.
One problem I have with 15s, depending on the pair/situation, is the foot chick can be too low pitched to cut through. But when using the hi-hats as an alternate ride surface I prefer the pitch and spread of 15s.
It took me several pairs of 15's before I found ones that were responsive enough, and with a solid foot chick, all the while not being overly heavy. Went through K's, Bos Turks, New Beats, and finally got the Paiste ME's and they are the sound/feel I was after. IMO they have a great balance overall, and sound amazing recorded.