Cannondale Optimo Cross.
I've got a LBS selling a used Cannondale Optimo Cross... They don't know what year it is or what model/class it is... but it seems to be a mix of Tiagra and 105's... And it may actually be my size... $650...
So it sounds like a great deal. And it's my size... But I don't want to buy this thing without knowing it's it's 2 years, 3 years, 5years, etc old... And I have no idea how good these bikes are.
Cannondale doesn't seem to list older models on their site...
This would be my first serious bike.. I'm looking at doing road biking and rail trails... fast..
2013 Kona Jake, 2008 Kona Major Jake, 2013 Kona Jake the Snake, 1999 Kona Muni Mula, 2012 Ridley Excalibur, 2008 Surly Long Haul Trucker
Look at the shifters. If they have a little red marker indicating which gear you're in they're 4500 series Tiagra. If they have a visible bolt, they're 4400 series. The 4500 series was introduced in 2007, I think, and is just being replaced this year. Those were pretty good components. If the bike isn't used, then the age really doesn't matter a lot. The Tiagra components on a 2007 bike and a 2011 bike would be the same.
You might be able to figure out the exact year using Bikepedia. Color and components are usually enough to figure it out. Is it light blue? It seems that 2007 is the only year that C'dale used "Optimo" int the bike names, and the 2007 Cyclocross Optimo 3 had Tiagra components with a 105 rear derailleur. If that's the bike you're looking at, I think it's probably pretty good. You could find something used for a bit cheaper, but it would be used. The 2006 C'dale Cyclocross also had a Tiagra/105 mix, but it had the 4400 series shifters.
Edit: I just re-read your post and saw that you do say that it's used. Given that, the price isn't amazing, but it's in the right ballpark.