So far I've only gotten helmets and glowhoo on HM Crota kills, so can't comment about Fang or Word.

But Oversoul is a blast and is solid in many situations. I agree with who ever said that it wrecks on Omnigull, also great if there is a Phogoth arc burn. It is actually better than Timepiece and I would say Timepiece was an underrated weapon even before pulse was buffed.

Abyss Defiant however, is hot garbage. Yes, it has its uses against wizards but other than that I'd pretty much take VoC every time (and I've kept one of those on every character I have) especially if I want to do solar damage on my primary.

Black hammer is as good as advertised, but that weapon is really frustrating if you get an enemy that dances (for example, if your fireteam decides to light up Atheon with grenades and rockets, you will be hard pressed to hit the critical spot). You MUST hit three crits in a row for it to be effective.

Swordbreaker is good against knights and totally OP against Minotaurs-Praetorians. It is not the best ranged shotgun, but the six shots, the power and the unusually fast reload on it make it very fun and useful. It shoots a lot faster than Felwinter's, but I don't have one with full auto, so can't comment on that. It has been a go-to weapon since the buff.

Light of the Abyss is one of the fastest fusion rifles and has a good combo of perks and mag size. Very good.

Song of Ir Yut is OK...its better than some of the vanguard machine guns, but I agree with others that it doesn't hold a candle to Jolder's, probably corrective measure (I've seen enough to know its very good, but don't have one) and definitely Thunderlord. Speaking of which, I actually think Thunderlord may be the best/favorite overall exotic heavy in the game. I have two Thunderlords and two G-horns, and while I'm always going to G-horn Crota, there are actually more situations that I like having Thunderlord. Not only is it useful in a variety of PVE situations, but all of my best Iron Banner streaks have been with Thunderlord. I also use it to complete a variety of bounties especially with the Dark Beyond-waking the hive. It makes quicker work of that onslaught of thrall than any other weapon I've tried (and I've tried a bunch).