I have just recently discovered TuxGuitar (well, guitar too). Since I am using Linux, I was really glad to find it :)
However, I have realized that a few things are missing, as I could not reproduce some of my scores. One is the more advanced repeat mechanisms, like Da Capo (D.C. al Fine and Fine). I know it can be simulated by repeating the part of the score up to Fine at the end, but it is a bit clumsy like that.
Same for Dal Segno. I think it would be great if TuxGuitar had these features too.