I've used both and have mixed opinons about both. But as my fingers become less nimble I am being forced to use quick snaps more as I don't need to tie them on as often as I do the loop knot.
i use 20 # brad with the thickness of 2 # mono. I sometimes lose larger fish when fighting them with the look knot. The brad slips through the small space at the end of the "eye" when under pressure. Never happens on small fish, just the bigger ones.
But sometimes the same thing happens with the quick snap. The jig slips off the quick snap with fighting big fish. Not quite as often as with the loop knot. Plus I prefer to use 1/32 and 1/64 oz jigs and must tie on a smaller quick snap or use a different rod when I'm using the 1/64 oz.
So as I said, mixed opinions about both. But I will probably end up using quick snaps as it gets harder to tie a loop knot.