Seems to use less power than the Mini Razor and has a better refire rate if I remember the Razor right. Also compliments the SNAC perfectly on my Barghest
And just like Tenacity I cant hit crap with a Razor, but the Inferno has a better projectile speed
Personally, I'm a better shot with the Inferno, but the MR can take down shields as well. It all depends on the rest of your loadout. In general, the Inferno is easier to hit with, but only does shield/energy damage (obviously), so it's really just a complement to a full loadout of hull-busters. The MR, on the other hand, can take out both hull and shield of a fighter, though it'll have more trouble with the shields of gunboats and be almost useless against larger ships, but it can be used with almost any loadout with at least some minuscule measure of success. It's also a lot slower and harder to hit with. Think of it as a mini-SNAC.
Obviously, though, the Inferno is an Outcast weapon.
Inferno is great for shield dropping, and none else. A SNAC can eat a hull like none other, though. Both together are a beastly combo
Razor has 18k to hull, that means that when pesky fighters show and the SNAC is recharging, you can dent them pretty good with that, shield and hull. If you want good Shield killing on caps and freighters, use Screamer mines.
All of that is meaningless if you're in a barghest, since fighter combat will never ever go well for you. Best you try and get an Inferno.