I've only attended a small handful of classes so far but I've enjoyed them. Some have been very work-oriented but some were more social; I've enjoyed both formats. I've been to a couple from my guild that were long (4+ hours) and towards the end of those I'm often in the mood to pack it in and go home but I know several of the ladies stayed a long time afterwards, working and chatting. I have old car accident injuries so my neck & shoulders need a break after 4 hours!
I seem to do okay talking while I'm working as long as I've got my things laid out properly. I'm not likely to cut myself or have bad workmanship, but I am likely to cut the wrong size piece out of the wrong fabric or sew the wrong two blocks together if I'm being too chatty. So I prep with post-it notes for each stack of fabric so I don't mix myself up as I talk. I'm a chatty person so I like that part of classes.
I'm still sort of a "newbie" but I've been made very welcome at every class and event I've gone to, guild-related or not. I was really nervous about joining the guild but it's been wonderful! I've learned a few things, seen some gorgeous quilts, and made some new friends.