Soldato
I would just clarify, it has a pretty high chance to spit out a single higher rarity level item, but frequently it's not actually a better item. I've had so many times that three blue pistols, often good ones, end up being a useless purple. It could just be very bad luck but I would say purples from the grinder have a high rate of being less wanted types. I've only got useless SMG's out(non elemental and not particularly high damage) and pistols, I've gotten one decent purple pistol, but loads of low mag size, low fire rate explosive or non elemental pistols that really. Almost none of my purples from the grinder have ended up better than other guns I've had. It's basically just another jackpot machine, you need to just keep doing it over and over and eventually will get something worthwhile. It is pretty epic trolling worthy to actually name the machine a grinder though
My advice is, if you have a great gun, stick with it, grind others and if the result is better than what you have(not in stats, but actually using it), then grind the old gun. Two of my best guns right now are two green beam lasers, I have purple(from grinding) lasers of pretty much every type and element yet none of them offer the damage output or usability of the green beam ones.
If you have a good beam laser with a +150% continuous fire damage bonus.... you're laughing.
As far as i can remember every weapon i've created has been better than any of the ones i put in. Though i've mainly put in white guns or green with moonstone.
Regardless of which, i'm struggling to see the point of the grinder at the moment. Maybe someone will document the best ingredients by the end of the year to make it useful in late TVHM and UVHM.
150% continuous damage lasers are my favourite at the moment, got a few great ones. Even better with Wilhelm's laser damage increase skill