There's no EQ aspects... it's a multi-band compressor. I guess you could say it works like an automated EQ, but that would be convoluting it.
You need to keep in mind that the setting has to be relative to your mix. You shouldn't necessarily have the same threshold as Andy, unless your mix is relatively the same volume as his was there.
It won't magically make the guitars sound better, but if used correctly, it will clear up a lot of low-end mud and make way for the bass guitar to cut through. It's more about enhancing the mix than the guitars.