The Tarmac doesn't have the reputation of the S-Works E5. They're not the same frame. Personally, I'm distrustful of dual-material frames - it's just gimmicky - and they're quite a bit heavier than the full aluminum frame. I'm fairly certain that the geometry is the same, but I don't know how they feel. Strange as it might seem, I don't think they're as desirable (in a market sense) as the aluminum E5s. $400 isn't amazing for a used aluminum/carbon Tarmac, particularly given that they're bonded aluminum and carbon.