I've played it a bit. Overall the game is quite fun, but I can see it becoming boring over time. Limited maps and game modes will do that, but I'm sure that will remedied over time. However, what maps they do have right now are downright beautiful; Very bright colours that blend well together, extremely detailed and over quite polished in an aesthetically pleasing way. And they got decent mechanics too I guess.
As for the character's, well, I guess I'll give my take on each:
Genji: High skill, high reward. Plain and simple, a bad Genji is little more than completely useless and a good one is halfway untouchable, weaving through teams throwing shurikens all the while murdering everyone with their own ordnance. Of course, with the open Beta just coming out an' all, most fall towards the former. Pro tip: His block can deflect any projectile in the game, including ults like Tracer's time bomb.
McCree: Alright, people complain about his stun grenade, but without it he'd be nearly useless a lot of the time. His ult manages to be one of the most powerful and one of the weakest at the same time as it is so, so easy to counter.
Pharah: Don't have much to say really, rockets are alright, mobility is awesome, but puts you in harms way.
Reaper: At first glance I thought he would suck. A slow, broody, Darth-Vader-walking assassin with stubby, close range shotguns that he pulls from his kidneys. I was wrong. So, so wrong. I vastly underestimated the utility of his slow-ass teleport and the healing orbs give him just enough sustain to keep fighting in team battles. The get-out-of-shit free button is also nice. Probably my favorite offensive character at the moment
Soldier 76: Easy to play, but has enough utility to keep him interesting and is effective in almost all situations. Sprint may be one of the most powerful mobilities in the game.
Tracer: Another high skill, high reward type. Didn't really play her much myself.
Bastion: Oh poor, poor Bastion, hated by so many and for only reasons I can deem somewhat reasonable. He does an absolutely ludicrous amount of damage in turret mode, and it capable of mowing down entire teams in seconds. But, he is easily countered with a little bit of spacial awareness (and maybe a sniper). I do feel he should just be the tiniest bit slower though, his transformations and healing specifically. Not much, but a fraction of a second would make a big difference.
Hanzo: Did you enjoy playing huntsman sniper back in TF2? Well then you'd enjoy Hanzo, 'cause that's all he really is, plus a wall climb ability and a ult that can wipe unwary teams with hilarious ease. Of the two snipers he's easily my favorite.
Junkrat: A vastly underestimated hero, capable of putting out a ludicrous amount of damage in a short period of time, a good player could easily wipe an unwary team with a couple magazines of his launcher, one of the less prominent ones however (probably because he's a trainspotting, schizo-looking motherfucker), though I feel he will get more play as the game grows. Currently my favorite character overall.
Mei: Blizzard always needs an ice mage, and Mei fits the designation like a glove. Ignoring the whole incredibly pandering 'Chinese Climatologist' angle, she is an incredibly fun hero with incredibly trolling and team play potential. Fucks tanks likes it's nobodies business.
Torbjorn*: Kinda boring. I thought I'd like him a lot more than I do, he's just so incredibly unremarkable.
Widowmaker: You blew it Blizzard, you were given one chance to shine and you let it slip through your fingers like WoW's subscriber base. I'm of course referring to Widowmaker's venom mines or whatever the hell they're called. Blizzard, buddy ol' pal Blizzard, you own the damn rights to Star Craft, you have a character named Widowmaker that lays down mines that crawl to enemies that come to close. Could you not put two and two together? Was the creative team hit with a bout of sudden-onset-retardation when given the chance to make the simplest of connections? WIDOWMINES you imbeciles! Just... How? You know what, I don't want to know, just fix it before launch and I might re-consider buying the game.
Otherwise Widowmaker is an unremarkable sniper with a deceptively powerful ultimate.
D.VA: So, you're going along enjoying a solid point capture mission, you're not doing too bad, but you're not exactly dominating either. Mediocre, but hey, you can't always be MVP. It's then a screeching facsimile of a woman's voice makes its way into your headset:
"Ell-Oh-Ell!"
You suddenly feel feint and the acrid taste of bile starts making its way to the back of throat, "What the hell was that?" you think, half-way convinced your mind just played an incredibly cruel joke on itself. A moment of silence passes and you're confident that whatever it was its gone now and you continue playing, trying your best to forgot what you just heard.
"I Play To Win!"
A sudden warm, wet sensation runs down the sides of your face, you risk a touch and your fingertips return red; Your eyeballs have suddenly started weeping blood. Not that you care, all you care about at that very moment is release, your wrists yearn for the welcoming bite of a razor blade while your throat seeks the endless comfort of a noose. You consider quitting the match for a moment, but you had just managed a sick quad-kill that would surely be the play of the game. So, foolishly, you press on.
"NERF THIS!"
All goes black for a moment.When you come to, blood, blood everywhere. The walls, the floor, the ceiling. A look at the in-game timer suggests you were out for no more than a few seconds and after a frantic glance around your studio apartment confirms your cat, Colonel Stubbs, missing. Your mind screams to quit the game, but your hands do not follow, continuing to push points despite the blood starting to jam the keys. You have to finish the game, it is the only escape now.
"Time to raise my APM!"
"I'm Numba one!"
"No Hacks required"
You weather the banshee's onslaught with heroic resilience, each syllable destroying more braincells faster your countless hours grinding paragon levels on Diablo III. After six endless minutes you manage to find yourself with your team on the B point. The enemy team was wiped one good push and victory, and release, is seconds away.
"Gee-Gee!"
You are gunned down five days later in a shoot out with law enforcement. In the last few days you have set an old folks home on fire, collapsed a bridge and bombed multiple schools. The media would spin it as an ISIL attack, just another maddened extremist. Little do they know of the real, more insidious reason. At least now you know peace.
TLDR; I'd prefer if she was North Korean.
Reinhardt: A real team player, great for making pushes towards objectives and otherwise assisting allies. Can't really hold his own though, as his massive shield can be easily out maneuvered and his hammer does very lackluster damage (Really Blizz? 50? It's a fuckin' rocket-maul!).
Roadhog: 'I'm a one man apocalypse.' This simple phrase Roadhog utters at the beginning of matches really explains the entirety of his character. More so than other tanks he is suited for solo play, he doesn't offer much to the team aside from his hook and he's often more than capable of dealing with whomever he catches by himself. I can kind of get why people see him as OP, but really, all he is is a straightforward, dumb brute character that can be outmaneuvered by just about anyone. Just don't get too close, 'cause that's his territory.
Winston: Underwhelming. Very underwhelming. If there's a character I dare call under powered its Winston. He shield breaks too fast, his gun deals pitiable damage and his ult has a tendency to as much a negative as a boon. The only advantage he has over most other tanks is his mobility.
Zarya: So, so powerful if played well. If you have the shields down you are possibly the most useful tank in the game. She can easily negate ultimates and otherwise render her team nearly unstoppable. Her ult's pretty good too.
Lucio*: My favorite support character. Fast, easy(ish) and can hold his own in a fight. Also, who can say no to wall running?
Mercy: As basic they come. Useful, but not too fun.
Symmetra: Strangely fun and useful on both offence and defence. Frantically throwing down sentries as chaotic battle erupts around you is a rush for reasons I don't fully understand. Also, portal, it's just useful.
Zenyatta: Eh, I have trouble clicking with him. Not that he's bad by any stretch of the imagination nor is really boring gameplay wise, I personally don't find him too fun. His health is deceptively good, 100 points of shield goes a long way.
*I'm too lazy to insert special characters.