I've been, but haven't stayed.

My son & his wife have, however. Last summer. And other than a few service glitches, they were quite pleased with it. Although, no upgrade (Hotel was sold-out for an air show).

As for the location, it depends on why you're in London. I personally like the neighborhood very much. First time visitors might find it just a bit out of the way from the main tourist venues. (But not to the extent of Maida Vale, Regents Park, or West India Quay). For me, however, a few extra minutes in a cab or on the tube would be a fair tradeoff for staying in what's basically a desirable and thriving residential area.