in terms of specs list, both bikes are pretty close. for some reason, I liked the Novara. please consider the fact that I am not a fan of Hydraulic (mind the spelling) brakes. I have not riddend the Novara, so my judgement is not that fair.
but, I have ridden a 2005 K2 Zed 4.0, ABSOLUTELY loved the ride and handling. Zed's geometry is quick, responsive and nimble. I believe that the Zed's have shorter top tube than some other comparable make and model. It gives you a more comfortable riding position but compromises on climbing.
For me Zed 4.0 was a great bike for 9 out of 10 rides. I would definitely give it a 9, in a scale of 10. my riding style is basically intermediate (aggressive) XC (if that make any sense). and I dont do any jumps and stuts.