11 is awesome 9 and 10 are the ones that are lacking
I loved 9. I'm probably one of the few who did, from the sound of things. 10, though, was very lacking.
I loved 10/Crossroads of Twilight, but I read it knowing I'd have 11/Knife of Dreams to follow immediately after. I think a lot of the dissappointment around it is the whole "This is what we got after waiting years?" aspect. For people starting new or catching up again, I think it reads a lot better than it would have for someone on the bleeding edge of the series.
And yeah, I hated 9/Winter's Heart.
Well, from the reviews I have read about Knife of Dreams they are pretty mixed. A lot still are ‘meh’. In fact, the last ‘good’ book I am seeing is Lord of Chaos. I’d have to agree to an extent, at least speaking from Crown of Swords and Path of Daggers (as I haven’t read past that). CoS was ok and PoD was good, but they don’t compare to Lord of Chaos and the prior books.
It depends whether you're won over by Mat at that stage, I think. Knife of Dreams focuses heavily on him and really develops his character, so if you haven't started laughing at him whenever he shows up by then, then you're not really going to like it.
Knife of Dreams also goes a lot faster than the previous books did, and reads a lot more like The Gathering Storm.