4 thousandth's of an inch certainly does not suck. I'm running at about 8 thousandths tolerance right now. (I've not really dug into finding out where the error lies, but I'm pretty sure that the fact that my machine is not as rigid as it could be has a lot to do with it.
8 thousandths is enough for press fit parts to not fit together. (so therefore I've been avoiding dong them.)
