The link you posted is a step up. 100v in, 115v out. Presumably the bigger, chunkier and more expensive the transformer the better.
FWIW I contacted Furman's tech support recently asking them if it's ok to use their US power conditioners in Japan (which are rated to run on something like 90v~130V).
He said that the only problem might be that 50Hz mains would cause the unit would see a higher voltage than normal and this might trip the surge protection circuit.
If that's the case perhaps other equipment would also see a higher than 100v voltage and a transformer wouldn't be necessary?
I'm thinking aloud so someone please correct me before someone gets hurt.