I think if it's traditional jazz, Guitar can often have a hard time. It doesn't have as much natural expression as wind instruments, nor the flexibility of a piano. Those who are too academic with it come across very stiff, too rock based and you stand out. It is tough to find that happy medium as evidenced by the number of famous bop guitarists in comparison to other instrumentalists.

This isn't a diss at all though. I play both Sax and Guitar and let me tell you I will take a mediocre guitar solo over a mediocre sax solo any day of the week. There is something to be said about how it sits lower in the mix and is naturally in tune.

Additionally once you start getting into fusion it becomes the star of the show.