Not worth it, IMO. You lose 4 sockets' worth of stats from the gloves and belt in addition to the lower stats on the items themselves (plus socket bonuses, plus shoulder enchant unless you're taking inscription for the BoP enchant on Ironweave shoulders). I'd strongly recommend that you practice your fakecasting, which in the long run will get you a lot further than the 10% resist chance granted by this set bonus.
It might still be worth going after just for the swag factor, seeing as there probably aren't very many people left who still have the summoning items and even fewer who have bothered to farm the set. Be forewarned, the drop rate on the shoulders is terrible. A few months ago I was helping someone who wanted the set for their transmog collection, and we both called it quits after the 150th Theldren kill.
