I really like them both, super tough choice. I've never really been a person who can tell a difference between two bikes beyond the fit and the Izalco and CAAD geometry is basically identical.
If I had to make a comparison, I would say the Izalco rode a little smoother but that's obviously because of the carbon vs. aluminum construction. I'm a big fan of internal cable routing, it keeps everything very clean so that was a big draw to the Focus. Frame and fork combined weigh almost the same. I'm only 140lbs so I'm not feeling any flex in either frame but you can see the Izalco has an ENORMOUS shell. But, I know a lot of big guys (175lbs +) that are super happy with the CAAD. Finally I raced the CAAD all during the last collegiate road season and crashed it 3 times. It held up like a champ, barely a scratch, that thing is a lightweight tank.
Thanks. It's a difficult decision between the two. Made more difficult by my inability to test ride.
Also, Focus prices are so good there's a bit of "too good to be true" feeling there.
I prefer the graphics on the Focus and like that they're a somewhat niche brand, but the CAAD has such a great history and is so well-reviewed that its tough to turn down. Also if I do the CAAD build it'd come with the new Red with the Yaw front derailleur.