Still no idea what%%% is but like you i tend to stick to my regulars occasionally trying another.
I find viva has a lower success rate than AW but some times it does come up trumps.
I think stay away from the ones that say "new in your town", "Best Service", "100% real" or they sometimes spell with as whit.
I'm not sure how VS works in terms of ad ranking but it seems quite often that the ads towards the end have the more realiatic looking photos and content that seems the most plausable.