The smaller a gun is for the platform, the greater its tendency to be finicky or require more maintenance.
There was a thread on here a while back about statements by Rob Pincus (one of the moderators here) stating that the micro-sized 1911s (the officer's sized 3-3.5" barreled ones) being unable to make it through a regular class. Thing is, those classes tend to be hundreds, if not a thousand or more, rounds in a short period of time. It's a crucible for reliability. Some guns will do it just fine, some other guns won't. Many guns may be perfectly reliable for 200-300 rounds (well more than one will ever fire in any defensive situation), but will get iffy when you hit the 800+ mark.
What I would anticipate is that in most platforms, the "compact" sized guns (roughly 4" barrel) will work just fine- no worse than the "full size" variants (tend to be 4.5-5" barrel). The subcompact sized guns (sub-4") may be finicky, they may be fine. But those tend not to be much fun to shoot- firing one for a thousand-plus rounds will be pretty uncomfortable; more so than the mid-sized guns.
To borrow the Glock model numbers (I'm not making any statements about Glock itself, they're just a well known brand with multiple sizes), the full size 17 would likely be great, the compact 19 would likely be great, the subcompact 26, if it handles things fine, would likely have you wishing you'd brought something more comfortable/suitable for higher round counts.