Does the darksaber that Pre Viszla owned have any advantages/disadvantages to a traditional lightsaber? I've never seen it deflect blaster bolts, but that's because Viszla's reflexes aren't fast enough.
None. The Darksaber does not seem to have any unique powers.
- It is just an ancient Lightsaber with a unique color (black) and shape (blade-like).
It doesn't appear to have any other properties besides a distinctive hum and the ability to block other lightsabers.
Since Pre Viszla is not a Jedi, he was unable to use it to perform any other Jedi maneuvers.
Despite the claim that only Jedi could use a lightsaber effectively, Pre Viszla seemed quite capable in his battle against Darth Maul.