I just upgraded from Komplete 9 to 10 (not ultimate). My assumption was that the Pianos and Session Horns would be the value components but I must say how impressed I am, at least initally, with Kontour. I have not got too deeply into tweeking it yet but the presets are excellent and I even had the basis for a track after being inspired by one.
The jury is still out on Rounds but it also weems useful. I need to get my head around its less than conventional interface.
Polyplex and Drum Lab just seem to give more of the same type of sound that remain unused in my Battery libraries. I am probably going to have have to force myself to experiment with them and see if I can make use of them.
The Pianos and Session Horns are certainly going to be useful. What a step up from the old NI pianos in K9!