Personally I am not 'into' the size thing. My husband is more than adequate (about 8 inches) but I have enjoyed partners who have been both larger and smaller. Probably the 2 best cocks I've had the pleasure of were both quite a bit bigger
but that was purely by chance not design.
As for the how long it lasts question I have always found that guys who just go on banging away endlessly make me feel less of a woman, its as if I don't do anything for them and I'm just a piece of meat. That's not to say I want them to finish in 5 minutes
but it is much more of a turn on when you feel you are turning them on and making them cum
.