Medium level carbon vs good alloy.

I have 2 other mates, one with a argon krypton carbon running full 105 and another with a 2006 F5c felt that’s standard. I have a Cannondale synapse alloy with campag Zonda wheels, carbon forks and campag veloce groupo.

We are sort of teasing each other who has the best bike. Of course they say carbon is heaps better then alloy. But I argue that its not.
My argument is that:
1. My frame is much much stiffer then the carbon frames. I have ridden the felt (krypton is only days old) bike and I cant tell the difference straight away. My bike is responsive and very touchy when sprinting.
2. I’m not sure about frame weight, but all three bikes weight about the same. We have weighed them all at around 8.5kg.
3. Of course the carbon feels a bit more comfortable on bumps, but I have carbon forks, carbon seat post, carbon handlebars, carbon stem and the bowed back end. So mine is not bad either.
4. The felt does not run a “complete” groupo. Mixture of different stuff, not all shimano. I run full campag.

My position is if you want a good carbon bike that’s stiff & light you must cough up the dollars.

Whats everyone elses opinion?