I mostly liked Necrophim when it ran in the Progs, especially for the art but also for Lee's twisty-turny plotting. There's some fantastic character designs all over the place, and I do like the characterisation of demons as sort of mentally incapable of doing anything other than betraying each other all the time (kinda like Blackblood out of ABC Warriors), allowing the fallen angels, mostly Uriel, to manipulate them in fun ways.
I'll confess that a re-read left me a little less enthusiastic. By the time you get to the end, the twisty-turniness is so relentless that it kind of left me wondering what any character's motivation actually was, and why I should care what the end result is for the peoplof Heaven, Hell or indeed Earth.
Overall, however, I remain fond of Necrophim, mostly just for the sheer balls of setting a story in Hell (and Heaven), and making use of the rich mythology surridungin different visions of them, especially Judeo-Christian mythology (I'm a proacticing Christian, but I hesitate to call this stuff 'theological reality...).
Far and away Tony Lee's best work for Tharg, he said uncontroversially.