The Nine have sent Xur once again to bestow Exotics upon Guardians and there are useful ones all around but Hunters are getting the same piece somewhat too often.
Guardians can find Xur on Giant's Scar, Io. Go to the landing zone, move through the big building and follow the path to the left. Near the end of the road, you will need to go to the left of the path, into a small cave. Xur will be located near the regional chest which you can also see on the map or you can consult the image below.
Everyone will love the weapon he's offering. Hard Light is one of the best auto rifles in the current meta and it doesn't suffer from damage drop-off as much as the rest of the class. On top of that, it leaves a distinct projectile trail so you can see which way your bullets ricochet so you can aim around the angles easier. It's fantastic in both PvE and PvP.
Titans are getting Mask of the Quiet One, which is also an Exotic that's useful in both PvE and PvP. Taking damage gives you ability energy, which will not have too much effect in Crucible but when you're getting showered by enemy fire in PvE, you will just keep spamming your 'nades and melee ability. However, when you are critically wounded, you will restore full hp and shields on kill, which is absolutely amazing when duelling other Guardians.
Skull of Dire Ahamkara is Nova Bomb Warlocks' favourite as it restores Super energy on Super kills. Tossing the giant explosive into a pile of thralls will be even more satisfying when it returns a ton of energy but it's also great in PvP since you can easily throw three or four Nova Bombs during a Control match when running a decent amount of Intellect and this Exotic.
Hunters are getting Ophidia Spathe once again. While repeat Exotics on Xur are annoying, this particular armour piece is great to have for Gunslingers. It will give them an additional knife throw charge and recharging melee with Gambler's Dodge will return both charges. In other words, you can spam traps with Way of the Outlaw or potential one-hit kills with Way of the Sharpshooter. Way of a Thousand Cuts' triple dagger toss recharges quickly anyway so it may not be worth the Exotic slot with this build.