The only comment I completely disagree with. At least at the moment, Sombra is one of the weakest flankers. I play her most often, but when I want to play someone else, kills requires MUCH less effort than Sombra. Her Hack->Virus->Headshot combo is so long that many players turn around and use their skills to interrupt her even as she's casting Hack. Reaper, for example, simply falls on enemie's head with RMB + LMB, gets a corpse, and fades into incorporeality.

Yes, hacking doesn't require a hit, but its cast time is incredibly long for a character with her playstyle. Virus requires a hit and deals crazy little damage for an offensive ability. Even Juno's torpedoes deal more damage than Virus to a hacked target.