Mim, Betrayer of Turin

[Fizanko]

And dont forget his drop.

On that point,

He will carry up to 4 exceptional objects.

I don't know if i was having really bad luck on Mim drops, but as shown in the screenshot in spoilers when i finally killed that unique, those "up to 4 exceptional objects" that appeared were in fact only 1 pair of steel shod boots "normal" (i mean no speed/free action/whatever brand) and with +/+ bonuses even worse than the truckloads of similar boots i already looted from my various dives.

At least i got my vengeance for past characters artifacts being ruined

[Sky]

Thats just luck. You still got to try. In theory Smeagol could (and should) drop The One Ring.

Afaik, uniques will drop better stuff the deeper down you are, so avoiding him until you are a few CL above his threat level should both eliminate the disenchat issue and also give you a bigger payout.

[Ingwe Ingweron]

Ehh, if I have a good opportunity to fight him -- clear terrain, no other monsters nearby -- then it can be worth maybe losing 5% of my damage output if it means that he won't get generated again somewhere more inconvenient.

Depends on what equipment @ has. If it's not one of the end-game or mid-game artifacts, I'll risk the disenchantment. But if, for example, I've got a mage that is wielding the Trident of Wrath, I'm not risking disenchantment. I'd rather wait and take on Mim or his kin at a more opportune moment.