Minor spoiler that most everyone probably knows....
I finally got around to getting the UP77 "Limitless Potential". The story behind it is fun, and I wish there were more things like this in the game, beyond the endless "Kill 'em all and let God sort 'em out" missions.
I feel like I'm swinging Thor's hammer around or something. As long as I don't run out of fuel cells, there's almost no point to carrying any other weapons around. Between the fire rate, damage, and no reloads, even an energy resistant enemy will get worn down fast. I'm already suffering from the curse of Bethesda Godhood, the point in the game where I can kill enemies by farting on them. This just puts the final nail in the coffin.