When shooting groups, the only things that affect me are the sights and the trigger. If the grip feels strange, I can still align the sights and work a decent trigger.
When I'm shooting in more dynamic situations, everything has an effect; grip size and shape, sights, trigger pull, trigger reach, etc.
I'm generally OK with a consistent, smooth trigger, so changing from a nice 1911 to a nice DA revolver (or striker-fired auto) isn't a big deal. Changing from either of those to an old DA/SA trigger with multiple hitches in both, widely varying trigger reach in DA vs. SA, etc., makes shooting difficult.
Pull weight makes a difference, but I find it's sort of related to the weight of the gun. I can handle a 10# DA pull in a N-frame revolver, but I suspect it wouldn't work so well in an alloy j-frame. I like 3# pulls in auto pistols, but a 5# pull works as well for rifles