I bought my first Behringer piece of gear many years ago with a small mixer. Since I have gotten several stomp boxes and have been more than satisfied except by the fact that batteries only last about 10 hours ( my MXR and EHX boxes last 100 to 400 hours depending on use). I guess Behringer wants us to buy the AC adapters, which I have done. Still a pain to run extra electrical lines in some cases. Anyway, the knobs on my ADI 21 and GDI 21 boxes are not well marked on the pointers. Makes recalling previous settings difficult. I have used both successfully to get good sounds, but there is a consistency problem due to settings being difficult to read. I've taken to scratching marks on the case, but that is not a real solution. Behringer should mark box settings more legibly.
My ADI 21 has been the best solution to controlling the pickup in my Dobro33, and has also worked superbly with my PW Crump bouzouki with an LR Baggs hotjack system as a parametric EQ. But, tired of scratching marks on the cases.