Personally I go for standard fuel, don't really fall for the whole "more bhp" and "better cleaning" marketing talk. I'm sure it does, but to a demonstrable degree in reality? There are plenty of other cheaper options you can use to clean out the injectors etc. without having to pay a few quid extra every time you fill up.
BTW, I've currently got a Mk5, and I've tried a few sequential runs of super in it. I definitely would not say there was a noticeable improvement, in any aspect.