I own both. They're both great units. I bought the Choralflange first, because I really wanted a good analog chorus pedal, and the fact that it did flange too was a bonus. GREAT chorus sounds, and really awesome felxibility. You have a lot of control over the sound, MIX, Delay Time, Rate, & Depth- Plus a sweep switch that makes the chorus shift over either 1 octave or 2. There is a small trim pot on the front that allows a volume boost or cut when the pedal is engaged too. I'm very glad I dropped the cash on that pedal. I can't really speak for the flange side of it though, because I barely used it and I'm pretty unfamiliar with other flangers as well.
The choralflange does amazing leslie sims as well (which is what I use it primarily for now.
As for the Deja Vibe, I have the miniature one, without the foot pedal. It sounds really really really good... when you can hear it. My problem with it is that it sounds really subtle, even with the intensity cranked. I've tried it in my amps loop, and before the preamp- and I can't really find a good place for it. It sounds great if you're just playing clean- but as soon as I add overdrive, it gets lost in the mix.
I've only had the Mini Deja Vibe for a few weeks, so I'm going to keep messing with it.
But if I were you, I'd definately get the Choralflange. It was worth every penny spent on it.
Anyway- good luck with the decision!
Ant