I always liked Christian but I can see why people consider him Edge-light or diet-Edge. he had a cool moveset, was good the mic, and I was listening to him on the Jericho podcast and seems like a cool dude. Wasn't jealous at all that Edge was way more successful. He was better in the ring than anywhere else, and for that alone, I think he is really underrated as a worker. I always felt like he did a good job of adjusting to whoever he had a match with. he could fly, do power moves (just not the spear), chain wrestle, etc.
The Killswitch was legit and I remember he broke Matt Hardy's face with it. He also had a cool variation on the reverse DDT. I missed most of wrestling after Benoit died, so I didn't see a lot of his solo work, so maybe I'm overrating him. I dunno.