I only ever do small pulls if it's my first time in a dungeon or I haven't been in a dungeon in a really long time (and as someone who hasn't touched expert in months, that last one is very likely). If I'm familiar with the dungeon, I'll pull as much as I can (provided the healer isn't new). If the healer can't handle it, I'll tone it down next time.
That said, I don't really care much for big or small pulls. I find that we're not out of the dungeons that much faster when we do bigger pulls.