I demoed the 1080 Foils before I bought my Karmas, rode my Karmas, and then demoed the K2 Public Enemy after that to keep from trashing my Karmas due to barely having any snow on the slopes.
This is coming off of years riding on racing stix before switching to snowboarding for a few seasons and then most recently switching back to skiing a couple seasons. For those two seasons I rode on Atomic GS:11's which are one hell of a racing ski.
Of the three... 1080 foil, Karma, and PE... the only one which carves... in the high-speed, stable, graceful, locked on-edge sense of the term was the Karma.
The 1080's are the most "fun" of the bunch in my opinion. Very light and easy ski to be lazy on due to their softness. The PE was a good middle ground, though they felt heavier than the Karmas and didn't return as much energy... lacked a little "pop".
The 1080's would be awesome for just screwing around on the whole mountain, the PE's would be great for a little more aggressive all-mountain, but of the three the Karmas are going to work best if you're really looking to push the limits on your skis for all-mountain.
FYI I'm planning on buying an older pair of 1080's or 720's for as cheap as possible to bring along with my Karmas for times when I just want to be lazy hitting little things on the slopes and runnin' junk moguls.
They're all very good skis though.
-Nathan