The hard fuzz doesn't approach vintage FF sounds to my ears. I tried it for a while and couldn't even really get all that close honestly. Changing the clip type got closer for certain things. At best, I got a reasonable approximation of the Si FF, but not really spot on. I've yet to hear anything that sounds and plays like a great Ge FF from the Axe-FX.
I hope that it gets added one day. It's such a fantastic pedal that's been used for so many amazing tones, and it's a shame that it isn't in the Axe-FX yet. I really don't want to spend the money on a Sunface, but if the Axe doesn't get a FF soon I may have to do it.
D