The crackled surface ones command a premium price, mostly on cultural values, not absolute taste. If looks and shape are paramount for your use, then they may be worthwhile. Otherwise it doesn't matter and the cheaper ones are equally as good.
The proteins continue to constrict forcing out more liquid and the muscle fibers become more pronounced, forming the "strings". It's not fast and it's not like they'll be bad or unpleasantly dry, but they could be better. Where steak is so tender anyway, it doesn't need a long cook to have a good texture.