Warr Guitars come in 8, 12 and 14-string varieties (14-string Phalanx series shown). There is no "standard" tuning (or rather, there are a number of "standard tunings", though Warr encourages you to try new tunings for yourself). Needless to say, the experimental nature of this instrument makes it a natural for prog musicians.
Probably the most famous Warr Guitar player today is Trey Gunn, sometime guitarist for King Crimson, who has both a Warr Guitar model and a tuning named for him. Less well-known, but every bit as good, are Mark Cook (99 Names of God, The Minefield) and Adam Levin (Dark Aether Project).