Thanks for the input.
Danny, I've listened to "who's gonna fill their shoes". Though I like the song, I find the high pitched harmonies a bit robotic. Could be the Digitech had to strech it to the limit; the other harmonies sounded fine.
I know that Russ also uses a Digitech.

Still not sure which unit to go for: the demo's on the company sites and the demos on YouTube are fine, but ofcourse made by the companies and thus made to sound to the perfection.
I will call the store and arrange a testsession.

Still I'd like to hear from people who use such gear live on stage. How usable are these units on gigs?