What kind of attack and release did you have?
It all depends on the source, but I normally compress my vocals with a fast attack, and usually start with a medium release (changes depending on the music). If you start around here, you shouldn't need as high of a ratio and threshold (not to say that it will sound better or worse than what you have done). Give it a try though, getting the attack and release right makes such a huge difference.
Just gave the mix a listen, sounds pretty nice although I agree it may be a bit too metal sounding. Maybe try some of the more "rock" Slate sample's, and get a bit more room sound in there. Also more of a stylistic thing, but on the guitar parts where there are octaves being played - I would have tracked the left and right guitars playing the rhythm part, and then done another guitar track as an overdub panned down the middle playing the octaves.