I know they're different... one's 4 stage, the other is a 6 stage. One has EQ tweaks and the other has a ramp to a different speed. I tried both yesterday at Bananas At Large and came home with the Psilocybe for a couple of reasons... first, the cost ($100 less than the Keeley) and second, I mainly use phaser as a somewhat light effect, mostly with dirt (which the Psilocybe does quite well). However, after spending the afternoon playing with the Psilocybe, I wonder if I made a mistake bringing it home over the Keeley. The Psilocybe will not be mistaken for a heavy phaser and the Keeley is a lot more intense. I wonder if I will have lingering dissatisfaction with the HBE and wish I had the Keeley. For the record, I don't think I'll ever use the ramp feature on the keeley and the psilocybe does have a real nice organic tone... just not in your face. So, I guess I will have to back to Bananas and try the keeley again (they have a great exchange policy). Anyone care to comment on the Keeley's ability to do light and play well with dirt?