I currently have the Uberschall, Powerball, IICP, 6505, and DRECT. I've also owned the Pitbull, Deliverance, Ecstacy, Savage, 800, and both Soldanos. Needless to say, I've tried a lot of the high gain modules! The Uberschall is my favorite for metal, so much that I sold my Uber Ultra after comparing the two. Channel 1 is this viscious Marshally upper mid monster of a channel that absolutely crushes. Channel 2 is even gainier and more mid angry like a Mark. Both channels can get ultra tight and crushing. This module is reason enough to try Synergy.
I basically boost every amp and module that I own, but the Powerball module is an exception - boosting it is just way over the top. The treble pot is very aggro and I'll keep it around noon compared to most other modules where I crank treble. I don't find the mids overbearing necessarily, but I do dial them back a bit. This is probably my second favorite module for techy, surgical riffing.
The IICP is also killer, and scratches the Mark itch, but I find it a bit tricky to dial in. It's generally woofy and can lose clarity quickly if you push the gain and treble. I keep bass and mids at zero, gain and treble around 1 oclock, and boost the fuck out of it. Volume one should stay pretty high however.
I've got a lot more to say about the other modules but don't want to turn this into a narrative. So far the 3 above are my favorites.
