Thread necromancy time!
So on 2/9/16 (yesterday) they went into the second closed beta, which is pretty much just a continuation of the original beta they turned off a couple of months back. They polished a bunch of stuff and now have some cosmetics that you can see and get in-game.
The way the cosmetics work is either you can buy them with real-life currency (this is assumed, because that part is disabled for the beta) or you can earn rewards in game. Every time you level up you unlock a "loot box" which you can open from the main menu which will give you 4 random items. The category for these items range from voiceover lines the characters will say, skins, emotes and an animation that will play whenever you get the "play of the game" awarded to you in the post game scoreboard (the animation will play out before it shows a clip of your play). You can also get a "spray" which is a little picture you can have equipped and whenever you press the key against a piece of the environment it'll tag the picture there. It's like cool or cute little clip-art or icons and stuff. You're guaranteed at least 1 rare and 3 common items, but you can get epic and legendary items too. This loot system is pretty much straight out of wow or any other mmo; white is common, blue is rare, purple is epic and orange is legendary. There are hundreds of things to unlock but if you do get duplicates you get an in-game currency corresponding with the rarity and can use that to buy specific items you want. This way people can earn what they want if they get lucky enough or put in enough time; otherwise you can buy whatever grabs your eye with your own money.
That being said none of these things you can buy affects gameplay. Everything is 100% cosmetic. Because Blizzard went with a buy-to-play model instead of a free-to-play/upgrade or a pay-to-play one all of the heroes are unlocked when you play the game and every hero that comes out will remain "free" (because you already payed for it). You pay for the gameplay and everything else is up to you.
The game looks like a lot of fun and looks like it has a lot of casual replayability. I was on the fence about pre-ordering it but I decided to today after seeing it again being streamed on Twitch and really wanting to play it. Plus I've started playing WoW recently in addition to still playing Hearthstone, so I'm being a big Blizzard fanboy. Because I know that Blizzard takes time to make their games I have faith in the product, unlike some other developers nowadays. I gave this a lot of thought before diving in. Plus $40 isn't too steep of an investment as opposed to $60 (although there's some cool digital extras that you get if you play the other Blizzard games).