Yeah, you can't beat fatebringer for thrawls.
I keep icebreaker and hunger of crota for all parts of crota. For the 1st part, I use fatebringer. Bridge part I use devil you don't (mine has field scout/13 clip). It does slightly more damage than fatrbringer, but no firefly.
For deathsinger and crota, I use another nitc or voc, depending what I feel like using.
Fatebringer sucks for thralls
Maybe not sucks, but I dont even like it as much as a scout. It feels so slow. You have to like come to a complete stop to shoot anything. Not good in CE. Plus a slow rate of fire is the antitheses of what you want on thrall.
Vex pwns it on thralls.
Pay attention in raids, most will be using Vex on that first part. Heck I think 5/6 of us were on this last one.
It's also best for 2nd part (bridge) too.
Firefly=most overrated perk.
Was playing more with vex just now, really is a monster.
Man I was stacking up the bounties, glimmer, and spirit bloom on Venus. So fun.
Xur's selling IB. Booo
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I bought a 2nd for my 2nd char. Would go a long way towards making him autonomous, although I'm not sure that's really accomplish-able since you will always probably need to trade inventory, so you might as well trade weapons too. Besides all that I tend to always be leveling stuff up, so I trade whatever I'm currently leveling between chars too.
At least not until bungie does a revamp of the vault system, which would be great.