Naaah, it's bascially the same as for everyone else, he just ends up killing Blah Blah easier than some. That's the thing, the edge isn't massive, because noone has to worry about anything with pissorff, especially there. I've ran the rat through most places and the only one where it felt like I was getting something from him that I wouldn't be getting form a random guard with pissorff was in slime pits simply because he can get more stacks on SMM so it goes faster. Slime Pits were a 0 problem dungeon even for a pissorff using berserker, but the rat did get it done quicker. A Gorgon in Taurog can do Vicious Steel using Pissorff (literally, that's what happened to me recently).
What I have seen from what you've been saying is that it might not have caught on with you yet that it's hard not to cheeze binlor because he's the obvious solution to most dungeons just for the glpyh, for anyone not just the rat (nobody but the rat needs the stoneskins, or the poking, just the glyph and maybe Crystal Ball). It sounds strange, I know, but can you imagine that to someone who's overused pissorff the rat feels like a less wieldly more gimmicky version? It's true. With him you're kinda working for a lower level solution mostly because of him, with everyone else because you just don't care.

Lvl 3 is when the boss DROPS for an above average pissorf guy, not when you start the fight, he's a late gamer by PoS standards XD
I'm actually enjoying him, despite all my grumbling. Seems like a nicely gimped version of your average Pissorff spammer, and he's got actual downsides to explain why he can spam through resists, everbody else doesn't. I kinda have him in the same rank as a Pissorf using Berserker (well, one who ran into Mystera and got Mystic Balance, the rat's more powerful) - you'll still easily beat anything, but it's not just a cheatcode and there's at least some gameplay to it and stuff. You need to convert more stuff, find more stuff etc (not saying you need to do very much, just more than most others, others just spam through resists, munch whatever and refill with whatever and don't even care about their pissorf damage). Namtar's Lair and Demonic Library were much easier for any of the guys I ran in there who did the exact same thing (90% of guys) - not very hard for a rat, but a complete joke for not-a-rat spamming pissorf. The Rat is best played that way I find, at least against phys res dudes, it's cerainly the fastest, and he's really well made for it, the problem is that he's also got downsides.
Like, anyone at all can just fast forward through Cursed Oasis with Pissorff, you can either skip the wraith because you only get cursed when you ding and then you munch on whatever and you just spam down the dragon like a chump OR you can kill the wraith at lvls 1-2 because you go through it's resists and blink (it has laughable stats) and then easily kill the dragon. He can't really do either, nowhere nearly as easy. For anyone else with the glyph that dungeon is really a joke simply because of the glyph. Even an (orc) Monk, who's probably the only class which is actually really bad with the glyph, laughs at CO if you go that way. For the rat it's just not very difficult.
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Today's daily was an easy one, thought I'd get at least one high placing, but there's some tough customers out there.