To be honest, I would see if I could stretch the budget a little. In the price range you are looking at a couple of additional dollars will quickly translate to better quality. Assuming a daily commute you will spend around 40 minutes a day on it. You might as well make sure it's an enjoyable 40 minutes.

I don't know the Cannondale, but seeing it's an 09 model, one would assume that's marked down a bit, so is likely to have better components. Your LBS should be able to tell you (though they may be desperate to shift if).