the Epsi wasn't designed for line level, so i haven't tried coming out of the eleven rack 1/4" out. it works perfect in the effects loop, plus you can put the epsi right after the amp instead of it being stuck in a place where you wouldn't want it.

speaking of a place you wouldn't want it: you would not want to run your guitar into it and then into the eleven rack or any other gear. the epsi loads an IR, which for all intents and purposes is just a fancy eq that rolls of highs. if you put your guitar into it, you get a crappy guitar tone....that's it.

i would ONLY use the Epsi in an effects loop or at very low volume coming out of your gnx4, or it will clip and sound nasty. the output of most effects units are made for line level, which is much too hot for the Epsi. the Epsi is made for stomp box level. so yes, you could run it as a stomp box after your distortion pedal, then into any amp.

to use it with Bias; you would have to find a way to come out of your device 1'4" with low stomp box level. not my department, so i can't help with that.

i bought the Epsi direct from Logidy for $199 shipped.

Ownhammer modern IR pack was $19 and includes about 500 IR's.