I just feel that, for an exotic, Suros is just kind of underwhelming, at least in PvE. Spinning up is interesting, but against most enemies you're either not getting to the ramp up, or it's just a good way to waste ammo. Dual-Speed (Focused Fire) just makes it into a high-impact AR, but without the range benefits that actual high-impact ARs offer. And while the occasional healing from kills is nice, why wouldn't I just use Crimson, where it's guaranteed and I can instantly refill the magazine too?