Batz,
I did a side by side comparison with S-56 and Wyeast 1056. 22L in each fermenter, same brew, temperatures etc.
I can definetely say the liquid yeast brew was much cleaner (nicer) tasting. The dried yeast seem to lack flavour when compared to the liquid version.
Pitching rates may have varied between liquid and dried, the dried yeast took longer to take off than the liquid.
I would use S-56 if there was no way you could get liquid yeast cultured up for an 'emergency brew'....
Cheers.