Smoothest bass response I've ever been able to achieve across the room, when paired with two subwoofers. Wide sweet spot for listening. Before the Blades, I used to have three different Dirac calibrations that I switched between often. Now I have two, but in practice rarely swap between them.
There are some practical benefits as well. It's nice having no cabinet vibration even at reference levels. The feet and built-in spirit level make it very easy to get them perfectly level -- something I never quite achieved with my old R11s. They're pretty forgiving in terms of placement, I think the recommendation from KEF is 9" out from the rear wall.
Assuming you buy new, registering them will get you an additional year on your warranty (6-years total).
And of course they are gorgeous to look at. One thing to note is that the
Frosted Blue finish on the Blades is *not* the same shade as the
Royal Blue on the LS50 Metas! Just something to note if you have both. I do, but fortunately they are not sitting next to each other.