ToME: the Tales of Maj'Eyal

My impression so far is that these guys are tricky to deal with because of their turret summons. Turrets don't hit as hard as say the war hound, but they seem much more durable so that taking them out quickly isn't easy, and still hurt when they hit. Terrain can be very useful since turrets don't move, but not all levels have corridors and such to use for cover.

I haven't played a ton of 1.6 insane yet, so I'm curious to get others' perspectives. How dangerous do you think Annihilator is on randbosses, and what are good strategies for fighting them?

I've found Annihilator to be a moderate nuisance as a randboss class, unless they get rocket pods with miasma engine or other nasty procs which can be rather dangerous. If you can't burst down a flame/(gun, sometimes) turret, get out of its range. It's basically a Gunslinger variant that deals less damage unless you're standing in the fire.