B+W MRC coating is
harder than glass so it is harder to scratch. I scratched a Hoya HMC filter while cleaning it and since then I only purchased B+W - I have not scratched any of them. The Hoya HD filters are supposed to be improved, but by the time they showed up I was already buying only B+W.
I would only use UV filters for protection on expensive lenses - as a thumb rule, if the filter ends up costing 10% of the cost of the lens, I don't get one for that lens. You may also want to have a look at
this article in which I dumped other useful information about filters.