I got the full Kontakt. It comes with a number of reasonable instruments. I got it primarily to gain access to products requiring full Kontakt (e.g. some Spitfire, etc.)
$199 is the best price right now, and beats the cross grade ($299). At least that was the case for me with the Kontakt instruments I currently own.
Re Crossgrade: if you currently own any Kontakt instruments, log into your account and add Kontakt Full to the shopping cart. It will automatically tell if you qualify for any type of "cross grade", i.e. an upgrade from a related Kontakt-based product.