i usually run with the guild as PUGs are a gamble right now. been in some bad ones and also been in good ones. had one where no one knew the fights and we wiped many times, but still everyone was cool and kept at it.
in our guild runs we will kick if you are just stupid (standing in crap or pulling agro by attacking the wrong mob). we normally wont kick for low dps as some people just dont know their class. we all go through that phase where we are learning, no reason unless its ridiculously low. i've been on the other side of it as well. just play your role and dont be an ass about things. seen a few guys mouth off on a guild healer or tank (and he was incorrect), that got him the boot real quick.