there aren't many apps in the windows store yet – i would wait at least a couple of months before considering of an upgrade. (it might be time for a sidegrade to ubuntu – no bigger step than to win 8…)
lots of applications may stay incompatible for a long time. microsoft will keep a barrier for free applications – a dangerous 'monopoly-play'…
i don't think, that there is a payed update for scribus – this must be a wrong information.