flopping two pair with K2 is very very weak. if the board pairs (and it often does), your second pair is totally counterfeited
Well, not to belabor the obvious, but if you flop 2 pair with K/2, there's only 1 board card (on the flop) that isn't a K or a 2, and you sure wouldn't mind pairing the board with the K or 2 (which is of course isn't very likely). Pairing 2 of the other 3 board cards would hurt, but the chance of it happening wouldn't kill the hand for me.

I still consider myself a newb, and I wouldn't play k/2o unless I got the flop dirt cheap (or preferably free), but there's something very fun about beating A's with a cheese 2 pair like k/2. 2 pair k/2 would be worth seeing another card most of the time (for me) unless I can put someone on a set.

But generally, everyone agrees that K/2o isn't much to get excited about.