Well, as I own maybe 10 sets from KK2, I will say what I can.
The shields of these sets were alright, I don't like how they were milky white and not old gray/bley (KK2 sets were around during the time of change, right?). But they made for great difference for heraldry. While I don't use the octagonal shield, I see them working as a pavise for crossbow men. The helms, well, were a hit or a miss. I like the Shadow Knight helm, works well for the "evil" stereotypical knight. Also with the helmets, Vladek's visor is very "evil" as well. The purple knight (don't remember the name) had a great helmet, had it come in a different color than speckled silver or purple it would be very useful. While I don't use the octagonal shield, I see them working as a pavise for crossbow men. Also, I believe the "Viking" sword was introduced in this era, which can be used for a claymore or, of course, a Viking sword. The set designs were absolutely horrendous, so I won't go into those since I can't find any good parts.
And that is all i have to say about KK2. Hopefully a line this silly and poorly designed won't ever come out again, but we can only hope for now.