I prefer smaller to larger. Women with smaller breasts tended to be more responsive than large breasted women. Same number of nerve endings over a greater area, I guess.
Honestly I've always wished my boobs were bigger. It's my only insecurity when getting naked, and will probably hinder me from ~having fun~ in the future. Porn, society and apparent expectations have ruined it for me (and probably lots of other girls). Only upside about small boobs is that they won't sag, and they're still perky after breastfeeding. Can't sag what's not there, am I right.
So far I've had to shove my ass up the guy's face, it works well as a tiny tiddy distraction. Especially if he's an ass guy, then anything can be forgiven.