I like my g34 and I am used to it, but even with more and more rounds through it it does not feel good in my hand as my other pistols do. But I shoot as well (or not well
) with it as my other pistols.
I think that feel and proficiency are two separate factors. If you only have one gun even if it doesn't feel good, practice will make for proficiency. Given options however, I would imagine people will practice more with what feels good, excluding external factors such as a carry pistol where might concealment trump other factors leading to a gun that does not feel optimal.