In my opinion, I'd say Light Beyond Nemesis due to the new raid. Being able to revive raid members faster is a HUGE bonus. Plus helms are the only thing you can't get from the normal raid level, might as well use an exotic helm right? I was having the same issue deciding between Voidfan Vestments or Light Beyond, I'm going with Light Beyond solely because of the raid. I do PvP often but the perks in Ligh Beyond are too good to not have. I'll rank up my Voidfangs when Xur sells the upgraded version.