To Zaku,

Either Susano Itachi or Edo Itachi, each one plays slightly different style.

Another info you might have missed that Edo Itachi can cast through immunity, therefore it's like Masked Man and Susano Itachi in 1 ninja. I think this is the real reason players use him.

Put sleep for 2 rounds on Wind Main, flower guard or root and can't heal can be quite annoying. it would make 3v4 instantly.

These days we have a lot of ninjas with immunity and team. You can still use Susano Itachi's chaos to stop if you have right timing.

Edo itachi dodges chase, which make hit combo harder to trigger,

Both are amazing. It depends on what team you're playing.

P.S. I don't have Edo, but I've fought enough to understand him.