idevice always has more teams competing (= more competition) so ya... its an undisputed FACT idev has more competitors aka more competition.
maybe this forum meant which gst has more skill? in which case it would be mixed because the top mixed teams would beat the top idevice teams (not crush them, but win)
but there are idevice players who always carry their team who i think could be as important of a core on a mixed team. Like sarah/noss/shadz/maybe a few others I'm missing could probably handle mixed tournament