Well, they didn't write their own songs, but they had a coupla weapons in their arsenal:
Harmonies learned from the 3 B's (Beatles, Byrds, and Beach Boys. Okay, that's 4 B's but stick with me),
Great songwriters
Blue-eyed soul
Chops and pretty pickin'
Hard-hitting vocals from Mark Lindsey- tuff and tender
Judge for y'self:
Oh, and if you can find the vinyl of the Kicks compilation (Edsel), it is all killa, no filla ;)