I have always stayed away from defense sets. It is tough to get them leveled up early on. Resist sets are more survivable in the early game and regeneration is more fun, at least for me. It is also easier to chase defense with IOs than resists. I know there isn't going to be DDR, but even with cascading defense failure, I still have my resists and regeneration. I do have a lv 50 SR tanker which almost impossible to kill in normal content. If we're counting invulnerability as a defense set (I'd say hybrid set), I have one of those too.