I have a Ridley X-Fire as my road bike; I got a deal on it, it mounts wider tyres for comfort (6'7, 190lbs), it came with Ultegra 6700, and I like the colors. Also, I liked the shop the most in my shopping.

Would I be faster on a dedicated road bike? Maybe, fractionally. I test rode several (Roubaix, Tarmac, others) and the Ridley felt great. It's not as twitchy as the Tarmac (aka 'responsive') and my proportions meant I'd have to do odd things to the Roubaix for fit because of the longer head tube.

Plus I've seen one other Ridley out and about, also a CX bike. Kinda like that.