In my personal opinion, Apotheosis Veil is one of the best warlock exotics when used correctly. Firstly, if you are a sunsinger and only use your radiance for self revive, you are kind of wasting your super (unless you are doing the hard raid or soloing the nightfall). Radiance, when used aggressively can be one of the most powerful supers available. Using apotheosis veil, means that if you use your super in a tight spot, you can regenerate all your health, and use it with radiant skin for a defense buff. The helmet also offers pure discipline, which is the best stat a sunsinger could want as it makes your grenades charge faster during radiance. Also, it is THE warlock exotic for the Crota fight, especially on hard. If you have not done the hard mode crota raid yet, your health does not regenerate during the final encounter. Using your super will regenerate your health, which is fantastic. Also, the helmet has the infusion perk which will begin health regeneration any time you pick up an orb. This means you don't have to use your red death and can use your exotic weapon as your Gjallarhorn (or whatever else you want to use) and be more of an asset to your team. Having the raid helm or Light beyond nemesis having infusion (regen health when picking up an orb) is good. HOWEVER, LBN's keeper of the pack perk is completely wasted on hard mode as there are no revives. Also, AV has the perk 'private reserves' which will regenerate your health when you activate radiance or drop a novabomb, so gives you more options to heal, and you don't need to have orbs to do it. LBN is also 100% strength, the least desirable stat, where as Av is 100% discipline, the most desired stat for sunsingers as it makes radiance more effective. Apotheosis veil is ugly. It's also incredibly useful for crota.