The Ridgeback has better derailleurs, 8 speed versus 7 on the Cannondale. The rest is a toss up, they are equally good.

Cannondale is well respected brand especially here in North America. Up until today I have never head of Ridgeback so I cannot comment on that brand. I know if I had to choose between those two brands, I would take the Cannondale over the Ridgeback just because I think the brand is better.

Think about it, if you ever had to sell the bike for whatever reason, which bike would sell faster? Most likely the Cannondale because Ridgeback is not a well know brand. This only based on my opinion.

Both bikes are worthy of buying so pick the one that you like the look of more. (Which is the Cannondale because that weird bend in the top tube of the Ridgeway is just plain weird).