Well with boobs, most guys generally prefer a nice handful. But ultimately, personality and face etc are more important. Tits are tits and boys are often just happy to see them regardless of size, so they're not exactly going to complain.
So it's kind of the same with girls. Most girls would probably prefer a well-endowed male but as long as it does the job, it doesn't really matter. Good sex isn't just about the size.