For me twas the JH Octavio by Dunlop, for me the octave up was bit shocking and the fuzz a bit to brash, now it lays in need of a repair sprawled upon a shelf!
They all spent quite some time on my board, but they always made me frown whenever I play them. They're not the type where by I hear a pedal, hate it, then flip it.
I owned TWO of each of Keeley's modded Blues Driver and Java Boost. Could never get them to work for me. Not sure why as they are built like tanks and I have heard others get great sounds out of them.