Wasn't really sure how to put my vote. I've never enjoyed sex or even O'd with any man until 5 years ago with my current partner. He's a little longer than average which sometimes hits my cervix which I love, but if i'm not super turned on that is very painful, but it's thicker than anyone I've been with too which can be good after we manage to get it in and past the hurting point. I prefer it to stay the same size, but if it were smaller we'd spend much less time getting it in!
I like my toys small. Usually 4" or 5" long and 1" to 1.25" thick. Anything longer simply won't go in any further (pretty sure I'm hitting the wall) so I just make do with however much fits. As for girth, I'm pretty tight, but if a toy was VERY soft I might try for something a bit thicker, if I was feeling brave.