The main thing that distinguishes Django from another jazz guitarist like Joe Pass or Tal Farlow is that he brought a different melodic and harmonic aesthetic to his improvisation - an aesthetic that came from his own musical background, rather than the more conventional American one.

His work with Grappelli is pure jazz - as is the duetting of Eddie Lang with Joe Venuti (both of Italian backgrounds), or the duetting of Johnny Van Derrick with Dizley. And others. The guitar/violin combination is one of the staples of jazz.

I repeat what I said earlier: Django brought a Belgian gypsy feel to the jazz that he played - whatever that feel was - and his style of jazz then became incorporated into the more modern "manouche" music we hear today. I don't know of any other gypsy-born jazz guitarists before Django (correct me if I'm wrong), and in that sense, he was unique.