This is always an interesting comparison, even though it so often shows up in the form of tiresome "Samurai vs. Knight" debates.
Reinhardt's ARMA essay referenced by Fearn is helpful. I recall following many, many threads on SFI and Netsword about this issue. My recollection is that straight blades, generally, cut as well as curved. This has also been my personal experience.
The curve (or lack thereof) and construction of a particular blade can certainly affect and influence the approach and technique used, as can the various elements Mabagani mentioned. However, I'm unaware of any convincing evidence demonstrating that one form is superior to another under all circumstances.
I do believe straight blades are superior to deeply curved blades in the thrust.