For me, it's a lot more about the build-up and how horny I am, as opposed to how much I shoot.
Generally speaking, I shoot more when I'm with girls (vice jerking off), which makes sense because I'm more turned on. I also almost always shoot more-- even if it's my second+ load in one session --if there is some kind of oral taking place to assist me cumming; one thing my gf likes to do after a longer fuck (if she starts to get sore) is kneel for me or lay under me and suck on my balls while I jerk off over her face until I eventually cum.
As for the physical quality of the orgasm, how much I shoot doesn't really affect how good it feels. There's been plenty of times where I didn't shoot very much but the orgasm still went on for short while; conversely, there's also been a lot of times where I keep cumming through almost the entirety of the orgasm. So how much I shoot doesn't really matter.
However, psychologically, there's a huge bonus for larger cumshots. My gf likes to get "covered" with cum, so she always likes my larger cumshots. Luckily, my average ones are apparently pretty large too; however, when I have larger-than-normal (for
me) cumshots, she really likes it. And, for me, it's a lot more satisfiying when I feel like I made a big cumshot (even more when girls comment on it). I love looking at a girl dripping with lots of cum, and thinking to myself "I did that
." In a weird sort of way, I kind've "respect" big cumshots in a way very simliar to how I "respect" a large cock. So, in that respect, it's somewhat of an ego boost for me when I shoot big loads.