As always, it depends. Sometimes the design misses the point of the original site and makes it harder to use for the folks already there. These tend to go over

As always, it depends. Sometimes the design misses the point of the original site and makes it harder to use for the folks already there. These tend to go over badly, since people would often rather leave than learn something completely new (and often less efficient). But I've also seen examples where the redesign goes well, usually because it maintains the general 'feel' of the original while making it look more modern/easy to use.