Well, from the looks of it, it seems that while Poncho, statwise, is superior to that of a Virtus chest, the other pieces are not, so basically, replacing the whole virtus set with Ganodermic set would be less effective than virtus. But, if you only replace the chest, at the cost of 200 Max LP (~14.3% loss of LP), you gain 28% Magic absorb, which may make it better, at least from mages point of view.