They're not really dissimilar enough to warrant separate lists, the graviton remains the sole shadow damage bomb while the electron does elemental and adds a shock chance more useful for keeping grouped monsters grouped and hurting, but it doesn't damage or shock as well as a voltaic.

Pros:
They suck (*rimshot*). They cluster entire waves of monsters into the smallest possible ball, making them choice targets for charge attacks and speedy disposal.
Cons:
They have a lackluster charge time and movement while charged.
The suction doesn't last terribly long, which means it's difficult even with charge time reduction uvs to pull off the combos that make it shine unless you're in a group chain placing them while teammates actually do the damage.
Their damage is not great and doesn't come until the end of the suction which means any heavy attacks that took advantage of the clustering possibly knocked the monsters out of the blast area already. The blast also flings monster around dangerously like a nitronome unless the monsters get momentum blocked from taking a shock tick. If you have enough ctr though you can place another vortex before the last one goes off, insuring that most of the monsters just get flung right into the new vortex rather than on top of you or a teammate behind you.
Not all monsters can be trapped by a vortex and many projectile dodge mechanics allow them to escape the vortex.
Monsters can still attack out of the vortex and the tight clustering can hide the attack indications making it difficult to dangerous to approach.

Basically, they're bombs that require a game plan going in because in just regular depth to depth play or soloing there's better bomb options. You're not going to want a vortex against a couple enemies, you want them for big wave spawns from an arena, danger room, jelly palace, or firestorm citadel. Even something with ridiculously short charge time like a catalyzer can't really be swapped to in the vortex's short duration to take advantage of by yourself, but a group of 3 friends with catalyzers can pack roughly 6-9 charge shots onto a group of monsters in a vortex over a placement or two and then blow up the whole thing, potentially clearing an entire wave of monsters in seconds.