I ordered from there as well. Good stuff. Their 304 couplings are nice and heavy which is nice for when you're worried about heat deformation while welding.
Mcmaster is awesome for many items but their stainless fittings are overpriced compared to buyfittingsonline. Example 1/2" 302 SS coupling, BFO $1.41 each, MC $4.59 each. In all fairness, the mcmasters are 1000psi and the BFO's are 150psi low pressure, but hey, we're not working in high pressure aps.