What is better sounding to you guys for a monk/druid/shifter build. Getting 20 levels in monk for perfect self? or getting 18 level in shifter to get the epic humanoid shapes?
Man, that'd be awesome if the shifted forms had the cool "glowing eyes" effect of perfect self. Sadly, I doubt it.
Otherwise, I'd say it's of little use to a shifter, if you need mind spell immunity you can shift to a form that has it.
I guess it depends on what form you want to be. The extra monk speed will be nice, but some forms have their special attack DC affected by their shifter levels.
Construct shapes don't have any DC rolls affected by shifter levels, so a high monk Construct would do well.
If you are going to focus on Humanoid Shape, then getting the epic version is the way to go.
So... it really depends on what you want to be.
btw, you only need 17 shifter lvls to get epic humanoid shape, unlimited times per day. At least thats what it was when I made my shifters.