for blues/roots style playing through a tube combo amp. I have been ogling the Vox Tonelabs but no retailer seem to stock them. I tried out a friends Boss ME-70 and it didn't really make much of an impression. Never been a Boss pedal fanboy to begin with. I don't want to completely mask out the sound of my amp. My old Korg Toneworks AX300G seems to have bit the dust. I actually liked this pedal except no expression/volume pedal was on it. Korg and Vox are the same company I hear and that's part of why I was looking seriously at the Vox pedals. So what sez you NBR?
I'd go with a pedalboard with as much analog content as possible. I find multi-effects tend to screw with the dynamics as well as sometimes add some digital artifacts. Especially for blues/roots, I'd go with a simple, mostly analog (except maybe a digital delay or a digital plate/spring reverb pedal).
Just one mangs opinion.
Also, what kind of combo are you playing through? If it's something like a Deluxe Reverb you've got an awesome reverb and trem already. ;)