User blog comment:AnotherRho/Views on ME2 Weapons/@comment-1388547-20110902075622

I've had some fun with the Firestorm, but I stopped using it before I started doing Insanity runs -- it's only really useful against weak enemies, and I prefer to conserve my heavy weapon ammo for special occasions. As for other heavy weapons ... I don't have much use for the Avalanche -- I think I've only fired it once or twice, ever. I don't really get the point of a heavy weapon that doesn't deal massive damage. I like the Arc Projector for general carrying around (though I don't use heavy weapons much in general), because it damage multiple targets and causes temporary paralysis. I also find the grenade launcher handy in some situations for the rapid fire and knockdown effect; in Garrus' basement I'll usually burn through most of my heavy weapon ammo using it to keep the Blood Pack away from the shutters. I typically only fire the Cain once per playthrough, but it's worth it -- I use it against the Praetorian on the Collector ship, which doesn't quite kill it on Insanity, but does shorten the battle significantly. Against the Horizon Praetorian, I use the particle beam because I have a hard time getting outside the Cain's blast radius. :-(

For non-heavy weapons, I don't really like the Geth rifle either, because it does so little damage, but the Revenant makes the game almost too easy if you have the AR accuracy upgrade -- at short or medium range, you can win most engagements by using Adrenaline Rush, blazing away with the Revenant until Rush wears off, waiting for your shields to recharge, and repeating until there are no more targets. Hardened Adrenaline Rush is definitely the way to go with the Revenant, since it lets you survive out of cover for the full duration of the power even if you're under heavy fire, which lets you take advantage of the absurdly deep clip on the Revenant. It's fairly easy to take down even the final boss on Insanity this way; I don't remember clearly, but I might not have even needed to scrounge for ammo. With any weapon, having a well-chosen ammo power is critical -- Disruptor vs. most mercs, Incendiary vs. krogan/vorcha, Warp vs. collectors or other tough biotics. For simplicity I generally use just one ammo power per mission, unless I'm up against something nasty that suggests a change (e.g. high-ranking asari or YMIR mechs).

My favorite weapons are the Mattock, Widow, Locust, and the geth shotgun, though I'll often carry the Tempest instead of the Locust if I have another weapon (like the Mattock or the Viper) that's good at medium range. The Mattock might be a tricky weapon for a Soldier, because of the small ammo capacity, though I've been meaning to experiment with an accuracy-focused Soldier run, using the Mattock and Widow along with Heightened Adrenaline Rush.