I own the just-previous generation Reference 1. I've been to the KEF headquarters in Marlboro township New Jersey and heard the new Blade 1 Meta in their stunning KEF Music Lounge. They are indeed, incredible. My situation is that the ones I own are SO good, and the room they're in is also incredibly good, so I cannot justify taking a bath on the sale of my current speakers just to get (what I feel is) a slight improvement in certain areas of treble.
Of note is that I previously owned both original LS50 and LS50 Meta pairs at the same time. There the difference also was very subtle. I couldn't play them back-to-back and level-matched, so my analysis is even more subjective but if one can own the Meta version of any of them, I would.