i have, and use both. Their quality level is about equal, both are top, top notch- the finish on the nepros might be a gnat's lash better, but hard to quantify.
That said, snap on still lives in my work kit, been using it for decades and I trust it. Not to say the Nepros is not as reliable, I just don't have 30 years of experience with it (just about 2 years with a nepros ratchet) and I can get superstitious that way.
Can't go wrong either way. It is easier to tell when someone puts your Nepros ratchet into their box, though- not too many people have them and they do stick out.
Matt