I've just bought a shawl from their womenswear collection for my fiancee's birthday. It's classically stylish, English-made, and looks like good quality, so I was happy to pay a little more that you'd normally expect.
I'm kind of in two minds about the rest of the collection, especially the menswear. Everything in it *is* the genuine article from top-notch manufacturers, but you'd expect a *bit* of a discount for buying them from M&S - for example on the Cheaney shoes, which seem to be exactly the same sort of price on the latter's website.
Overall though I think that this is a good move from M&S. Sure, it's a small capsule collection with limited sizes and availability (so either way it won't have much of an impact on their bottom line). But it's an important signal that they want to offer some excellent quality, indigenously-made clobber alongside the Far Eastern-manufactured low-end stuff.