Finished my first attempt at a CGB today and I'm feeling a bit let down right now - I knew there would be warts but there were more than expected. A few things that will go down as learning experiences:
1. There was too much work that happened on the neck and fretboard before gluing them together; as a result, the fretboard didn't really lay down flat on the neck and there are gaps all along the edge (despite full clamping).
2. Using small brass eye bolts as the tail to hold the bottoms of the strings didn't really work.
3. I'm guessing that the bracing that I installed in the body wasn't perfectly perpendicular; the neck seems slightly twisted in relation to the cigar box body.
4. There's significant buzzing in the body when I play the top string - not sure where that's coming from
5. I spent a lot of effort to try to get the action relatively low, but I must have some bad frets because playing up the fretboard results in buzzing in places and straight-up wrong notes in others. Frets must not be even in height.
6. I'm having a really hard time getting the strings to stay in tune. Finding the "in tune" sweet spot is really hard, and they don't stay there. May be related to item 2.
7. The bottom string, the high G (I went with GDG) seemed really loose for some reason - didn't seem to have much tension at all when in tune.
8. I got a CBGitty piezo pre-wired pickup and jack, but quickly found that the walls of the cigar box are too thick for the jack - it doesn't protrude at all through the open side to allow me to attach the nut.
Those are the big ones - I'd love any insight anyone has on any of these issues.
I have another box and plan to try another one!