Sombra is basically the Overwatch version of the DDOS script kiddies who bring down services like Steam and PSN. She takes crap you rely on, she breaks it and then she disappears. In the right hands, I think she's gonna be devastating.
During BlizzCon in Anaheim, California, I got to play a couple of games as Sombra, and it was a little overwhelming, to be honest. Sombra's toolbox is vast and versatile. She can hack characters to disable their abilities for six seconds (though thankfully not their guns). She can hack health packs to isolate them for whichever team she's on. She can hack Torbjorn turrets and knock them out of commission. Her ult lets her hack everybody in a large vicinity all at once and destroy barriers and shields.
And that's just her hacking.
She can also toss a translocator grenade, and she can teleport to wherever it is at will for a full 15 seconds. For some reason, she can see enemies at half-health or less through walls. Oh, and she can turn completely invisible, run around and unload an SMG clip into your fleshy, unprotected backside. She will shoot you in the butt.
That's... a lot of stuff. In practise, I found myself playing her like a stealthier Tracer. I'd use my translocator and invisibility to get into the enemy's back line, hack a character and maybe a health pack, and then get out. The invisibility + translocator combo makes Sombra deceptively quick and evasive. Her SMG isn't as damaging as Tracer's guns, but her hack leaves them temporarily stripped of their abilities, and if Sombra can't finish the job, hacking also makes enemies visible through walls to your teammates. Essentially, she can create a path through the level for attacking teams, hacking health packs and marking enemies as she goes.
It's super fun. Invisibility is quick and empowering, and arcing a translocator so that you teleport at the zenith of its flight feels phenomenal. There are so many ways to get around as Sombra, so many new ways to think outside the box. Most of them are deliciously devious. Her SMGs, meanwhile, pack a satisfying crunch, and they have large magazines. They're best up close, but they can do so-so mid-range damage, which is more than can be said for beefier harassers like Reaper.
But that's hardly the only way you can play her. Sombra strikes me as a counter to all sorts of tried-and-true Overwatch strats. Again, she can knock down barriers with her ult, which will certainly do a number on tank-heavy pushes. If you main Reinhardt or Zarya, prepare to be frustrated. Or let's say you have a Sombra sneaking around and surgically hacking supports like Lucio, Mercy and Ana. So long, sweet, sweet heals and power-ups. Got a big push coming off Lucio's ult? Not any more, you don't.
I worry that she might be able to influence the flow of matches a little too much. Again, though, I've only played a couple of games as her, so I need more time before I render a verdict. And don't get me wrong: She does have weaknesses. In a direct firefight, her HP falls apart like all hacker movies except the movie Hackers. While she can outmanoeuvre other harassers by using her translocator to teleport to safety (or even a health pack), they chew right through her in a shootout. Any damage can knock her out of invisibility, making her especially vulnerable to AOE attacks, explosions and big ults. Anything that makes her visible (think Widowmaker's ult or Hanzo's sonic arrow) is also dangerous. Lastly, I stupidly stumbled into more Junkrat traps than I'd like to admit while invisibly slinking around the other team's back line, so that's something to look out for as well.
Still, she has some mad-powerful abilities, ones that can easily turn the tide of battle. I'm not sure exactly how team compositions will shift and re-settle once she's in the game, but one thing's for certain: Overwatch is about to change.