I've got a Centurion Ironman Expert, and aside from it sounding like a POS from Wal-Mart (Mine needs a number of things replaced) it's a great bike. I'll be modernizing it at least somewhat, not sure if I want to go with brifters and 9 or 10 speed, or bar ends and 8 or 9 speed. Depends on what I feel like spending. Either way, it's the bike I decided on instead of saving up for something made of carbon fiber.
I also had a Schwinn 564 when I was first getting into cycling, which is probably similar to that Cannondale. It had a very harsh ride. Unless the road was perfectly smooth, I just didn't enjoy being on it that much. Of course, I don't know if the Cannondale will be that bad.