I have no experience with the Digitech, however, the B3 has a lot of friends on here, and for good reason. Easy to use, sounds good and built to last. Add in the Expression Pedal and it's pretty versatile too whether you use it in front of an amp or as an amp modeller/DI box. It's got a USB port, so you can plug it into your PC as a soundcard for a DAW, or download Zoom's Editor software to play about with your patches.
The downside is that it's a bit limited if you want more than 3 effects at once.
It deserves a B3x or a B5 version, but this is highly unlikely.