I have little experience all of the ones I have sucked or played with were cut and 5-7in I think i'd be nervous about sucking on a 8-10in as I like to take it all in my mouth, saying that I really want to try and give and receive anal and again a huge (long or fat) cock would scare me.
I'm likely prejudice but I like the size and shape of my own cock and would like to find the same.... minor exception would be, I would think as a first time it's a bit much for anal...
What's your Preference?