The q20 has a number of effects: reverb, pitch, EQ ...
Digital technology allows it to completely edit any of the 100 factory presets and save them in the 200 user presets available.
The connection: in / Adat out, in / out SPDIF in / out analog (sym or asym) jack & XLR in sync, in / out mid, bypass jack.
The comfiguration is quite simple, but the edition of the program is complicated and long, for by putting against time you can get "the fact that we really want."
The manual is well done but unfortunately does not replace the hours of manipulation required when you begin to edit the presets.
The effects are very good, especially when using the in / out digital.
I use mainly reverbs (which I fully editable from my microphone and my local) on the catch of his acoustic instrument strings.
I have an alesis q2 for 10 years and I bought two q20 (the alesis q2 is the same machine as the Q20 but without the in / out SPDIF)
The price / quality ratio is simply unbeatable views that we find q20 200 or 300 euros opportunities.