Tried out the Digitech Whammy and BOSS PS-5 this weekend and wasn't really impressed with either. Can't really see using the harmonizer functions - just sounds too cheesy and synthesized. And neither did 2 octaves down well (although it might've been better if I'd remembered to use the neck pickup). Although the Whammy's chorus like Detune function was neat.
So I thought I'd look at more specific analog octave pedals - 'cuz really its the idea of the Jack White one man band (plus mediocre percussion) I want to emulate - not necessarily his tone (with the Whammy). So having an OC-2 (the discontinued analog bass octave pedal) and a fuzz octave like Fulltone's Ultimate Octave or ZVex Johnny Octave would be ideal. Both ostensibly emulations or homages to Hendrix's Tycho Brahe Octavia. Dial them in and click them on as required with no fiddling. Lay down a bass line in the sampler, then click over to do some screaming leads.
But then I tripped on the OCTRON. New, all analog, one octave up and one octave down - and sounds great from the samples. But availability could be limited since there's one guy hand building them.