Very nice. I'm a Sunsinger when I go PvP myself, partly because I enjoy it, and partly because the benefits fit my play style. That said, you both reinforced suspicions I had and taught me new things. I'll be tweaking my build a little bit because of this video. Well done!

That was a really cool breakdown actually. I have wanted to get exact numbers but didn't have the patience or time (see what I did there). A bit long, but there was a lot of good info, so I am not sure where you could have cut it down.

As a frequent gunslinger, I find it abhorrent that a Sunsinger can withstand a golden gun shot.

That being said, I now know this - thanks to you- and can prepare for it.

PS: If you need any help with hunter pvp stuff, let me know. I'd be proud to contribute to such quality investigation.

Wow - that was definitely one of the best 'informative' videos I've ever seen on youtube. It might even convince me to try running a sunsinger in Crucible!

I'm a Melee Machine and love the claws of ahamkara!

Fantastic video, especially enjoyed the stats and research. Will be changing my loadout for my Sunsinger now!

I don't Warlock much in Crucible, but it helped me know how I can fight them a little bit better :). Also, had no idea that Sunsingers could survive a golden gun! CRAZY!

If you need help with Gunslinger, let me know, lots and lots of experience as a throwing knife-wielding murder machine. Can't wait to see the numbers on Hunters.

Which is funny, because it was literally one of the last things that you talked about.
Either way, that was an excellent video. Despite Sunsinger being my main since I could unlock it, I admit that a lot of the stuff about it was more or less guess-work and assumptions (figured that combining Fusion Grenades with Touch of Flame or Viking Funeral was pointless). Nice to see some concerns validated or allayed.

Now here's the things that I take issue with:

Heart of the Praxic Fire is an excellent PvP exotic for a few reasons:

Carry more ammo for Fusion Rifles- The Mythoclast is an extremely powerful Crucible weapon, hindered by the fact that you can quickly burn through the 210-round ammo supply. HoTPF boosts that ammo up to 262, allowing three more mags before you need to find ammo. While running out of ammo in Crucible isn't a serious problem, this perk is the only one that can increase the Mythoclast's ammo supply, since it's not classified as a "special" weapon. Obviously also useful for Fusion Rifle enthusiasts (I see you favor the Pocket Infinity yourself).

Carry more ammo for Heavy Weapons: Almost invaluable in the Crucible. If you don't wear Raid legs, this solves the issue entirely. Pretty much speaks for itself (I often have enough Machine Gun ammo to last through another Heavy drop).

Praise the Sun: Here's where it gets good. And keep in mind that all of these calculations are without taking into consideration Radiant Will (Radiance duration extended from 14 seconds to 17 seconds), which compounds the PvP lethality of the player.

Grenades:
In your video, you point out that at 0% Discipline, Radiance refills your grenades in 3.5-second intervals. HotPF is a Discipline-focused piece of gear, so no matter how you build your character, you will always have a minimum Discipline rating. Mine is 59% thanks to a rating of 139, which applies to the existing cooldown tremendously:

0% Dis+Rad. = 3.5 second cooldown
59% Dis+Rad+HotPF = 2.06 second cooldown

100% Dis+Rad = 1.5 second cooldown
100% Dis+Rad+HotPF = 1.3 second cooldown

With a base duration of 14 seconds, HotPF gives you up to ten grenades that you can throw. It may not seem like much of a difference between 1.5 and 1.3 seconds, but that's an entire grenade throw over the course of the Radiance, assuming you run around with 100% Discipline.

-Paired with Solar Grenades, you can coat an entire room with grenade blasts and an AoE burn, consistently putting three Solar grenades on the field at any point. Say you're in a room with enemies coming from two different doors. You could consistently block both doors with Solar grenades for the entire duration of your Radiance. Area of Denial does NOT get better.
-Paired with a Firebolt grenade, you can clear an entire room of enemies without ever setting foot inside. Each grenade will tell you the location of an enemy, and it only takes two Firebolt grenades to guarantee a kill. Since each Firebolt burns multiple enemies within its radius, you can spam blindly and guarantee multikills.
-Paired with Fusion grenades, you are pretty guaranteed to one-hit kill any enemy that you see in front of you, since you have extremely little cooldown between throws. Wreck shop.

Paired with Touch of Flame (and Viking Funeral), even the enemies that somehow escape are easy pickings for you or your teammates, since they're almost guaranteed to be on fire.

Melee:

While the melee charge time isn't super-impressive during Radiance, there are important factors to note.

0% Str+Rad = 15 seconds (0.933 charge per Radiance)
0% Str+Rad+HotPF = 9.7 seconds (1.44 charge per Radiance)

100% Str+Rad = 7.5 seconds (1.86 charge per Radiance)
89% Str+Rad+HotPF = 5.0 seconds (2.8 charge per Radiance)
100% Str+Rad+HotPF = 4.6? seconds (3 charge per Radiance?)

Unfortunately I don't have gear that will take me to 100% Strength, so I had to base the results off of an 89% Strength rating, applying them to what seemed a reasonable logic. Even at 89% though, a strength-focused HotPF user would not only fill two one-hit-kill melees in this time, but he'd have another one almost full when it was all over. A smart Sunsinger with Fireborn will usually wait until his target is within melee distance before resurrecting, allowing him to immediately make use of a charged melee, and in Control, enemies are rarely alone, so being able to get another melee charge up instantly is incredibly helpful, let alone two, possibly three.

Any way you look at it, the practicality and usefulness of the Heart of the Praxic Fire in Crucible can't be denied. And that's without going into the different perks (such as Gift of the Sun, which almost guarantees maximum grenade output, as it overrides any delay between grenade throws).

Here's my personal build:

I like to have some agility at the expense of some recovery, because if you're under fire while recovering, odds are a tiny change won't make a difference, and the few extra inches of height can sometimes make all the difference you need to reach a platform.

Great video, though. Definitely looking forward to your next ones.