So. I tried the ElectroHamronix Slammi Plus Pedal.
What I saw in this vid made me want to try it : the detune/chorus you control with the pedal, the ability to make huge DiveBombs... I had to try.
BUT as there was no vid with a bass, I didn't buy it right away. So I waited around 6 months for the store near me to get one - no presure - and finally tried it.
Short version : it's nice, but I didn't buy it.
Long version :
The pedal is good, classic looking, and combines harmony, octaver, pitch shift, and it can go both ways up and down, with a pedal control. Dry/wet blend, switches to change the effect, it's fairly compact.
What I wanted the most was this "chorus" like effect with the detuner, where you can increase the detuning, hence the chorus effect by using the pedal. That is RAD. Loved it. Very cool, you have a slight efect on the song, and you can enhance it for letting strings ring or solo part.
OctaveUp felt very artificial, octave down was great but you can go up to 3 octaves down, where it's inaudible. The harmonizer is nice, you have minor and major third, fourth, fifth... pretty cool but not too useful IMO. YMMV.
It has a lot of features, but what decided me against buying it was
--> Impossible to change the effect on stage. You have to tweak small knobs and switches to change directions of effect, etc.
--> Octaver is good but I won't use the 2nd and 3rd octave, and up it sounds not good to my ears
--> It's too expensive for a variable CHorus pedal.
I found a Live6 BassPod XT Live, I'll get it this week end. For the price of the Slammi+, I'll have the emulation of amps (nice for my band where we rehearse with headphones) the Chorus that shifts with the pedal, but also the flanger and Phaser and everything elese. So even if I use 10% of the BassPod, it'll be better than the Slammi.
Which is nice, but not adapted to me.