My main thing with the Kami is I see alot of people not get a turn 1 bird, and drop a turn 2 SotF. In these cases they are tapped out for the Kami to swing in and take care of it. And that is the end of it till they see an Eternal Witness or another SotF. The first game will more than likely be difficult, but after you board in, games 2 and 3 should be a breeze.
But the main thing is speed, whether it slows them down a turn or not, being able to kil off the survival right after it has been played (turn 2) is alot better than kill it off turn 3 or 4 or 5. Since they have already searched for what they need and will just kill you(or just be a threat) with what they have. But hey, just my opinion... :p
