I’ll say right off that I have the least experience with the MNTIS cannon, but I’ve found great utility and synergy for all Zane’s action skills.
The Barrier is great, especially once you figure out the augments. All-Rounder is pretty much a guarantee for me when using this skill; the 360 coverage/amp damage is great when you’re against big mobs or boss enemies with really large attacks. The Deterrence Field is helpful for keeping melee enemies away from yourself or the clone (in my experience, melee and splash kill the clone more than anything else). I’ve seen DF stagger enemies mid-jump-attack many times, and it peels away shields while it’s doing it. Distributed Denial may be one of the most broken skills in the game, but it does have a few useful tricks. Combine it with an All-In, Big Boom Blaster, or any other booster shield, and you will be swimming in the things. The Whiskey Tango Foxtrot explosives proc as well, providing another layer of deterrence, but putting some distance between Zane and their splash. A Black Hole or Void Rift shield with ASS anoint can turn the Barrier emitter and the dome itself into a kind of trap. Their singularities originate from the Barrier emitter, as well as their respective novas and homing spikes. Combined with Deterrence Field, this gives you a very tight group of staggered, sometimes frozen enemies, ripe for splash damage. The other augments are kind of meh, as are the skills beyond Distributed Denial, but it definitely has it’s upsides.
The SNTNL drone was my go-to skill before I started using the Clone. It might be worth it on just the SNTNL cryo/15% movement speed anoints, but damned if it doesn’t constantly proc Seein’ Dead and Good Misfortune. I love drone delivery, since I tend to run 2 action skills, instead of one with grenades. Keeps the It’s Piss and Mesmers in the fight. It’s also his only original action skill that can be deployed in almost any place/time. The clone won’t summon on certain terrain, and the barrier emitter will break as soon as it hits Killavolt’s floor. You can also set it to attack a specific target, where the clone will attack whoever it pleases. Which reminds me, the SNTNL always procs Trick Of The Light, since enemies can’t target the drone.
I love the clone. I’ve heard some people call it a “dumb AI”, but like any other action skill, it’s a tool, and it’s on you to use it effectively. That said, without Double Barrel, Donnybrook, and Boom Enhance, you’re looking at some diminished capabilities. I enjoy Fractal Frags for the same reason as Drone Delivery. Old-U has been a lifesaver, especially when everyone is dead, and you end up in FFYL because of some stupid barrel or residual explosion. Double Barrel can be one of the most fun, interesting skill in the game. While the fire patterns of the Clone make it ineffective with certain types of weapons (continuous beam and certain full-auto esp), it can absolutely wreck with others. The Hellwalker, Rowan’s Call, and Trevonator to name a few. The Grease Trap is awesome, because you can be spraying the Hot Grease while the Clone uses the Fire Starter mode. The clone is also great with Launchers, and other weapons that eat ammo (Tizzy). I love handing him a RYNAH. And oh man, weapons like the Flipper, with Clone ammo regen anoint?
Oh, and of course, the switching with the clone when you find yourself falling to your death.