YouTube Gaming: what it does right and what it needs to work on
The short answer is I think they're on the right track. In a lot of ways this is the same content that's always been on YouTube, just re-arranged, but I appreciate how they've rearranged it. When you hit the site you get a nice big (but thankfully, muted) featured broadcast front and center. There're fly-in menus on both left and right. On the right are Channels. If you Subscribed to a gaming related YouTuber on the old site, that Channel shows up in the right side menu.
What's new is over on the left side, where there's a list of games. Now you can Follow games in the same way you'd subscribe to a Channel. The difference is you'll get content related to that game from a variety of people. It's a great way to find new content about a game you enjoy.
If you click on one of your games you'll hit a page devoted to it with videos and broadcasts broken out by type of content, with tabs like "Live" (for active broadcasts), "Reviews" and "Let's Plays." There's also an "About" tab that tells you (via text) about the game and a tab to show popular content related to that game, regardless of the type of content.
I'm not really a game broadcaster but I gave it a try on YouTube Gaming. It was very easy to set up, though Google isn't offering it's own software to enable broadcasting. They'll point you to their "Guide to Encoding" which lists "Verified" broadcast software. They also support OBS (Open Broadcasters Software) which seems really popular among my friends who broadcast.
Since I am a noob, I decided to try one of the Verified packages, XSplit. It was dead simple to install XSplit then log into my YouTube account through it, after which I could update my broadcast title and description and start broadcasting at 1080P. Here's the archive of a few minutes of Diablo III that I broadcast as a test:
So as I said, it's a good start but there are some issues Google needs to address. First of all, there's no easy way to Share, embed, or "Watch Later" a video from YouTube Gaming (at least none I could find). While you're watching a video you can just change the domain from gaming.youtube.com to www.youtube.com to see the video in regular YouTube and do all that stuff, but that's an annoying extra step.
Second, there's no easy way to get a custom URL for your broadcast channel. What I had to do is use a Google+ page that had the same name as my personal blog, then I created a YouTube channel for that Google+ page, then I got a custom URL for that channel (they call it a 'custom' URL but Google generates it for you based on your name), and finally I copied my old channel to this new channel. Whew!
I think you could skip the Google+ bit and head to https://www.youtube.com/account then click on "See all my channels or create a new channel" and add a new channel that way, using as a name what you want your custom URL to be, and hoping for the best. (You can probably tell I wasn't taking notes during this process and was just trying different things until I got the results I wanted.) Anyway, it's clear that Google needs to offer an easier way to set up a custom URL to share with friends.
Third, I've heard some broadcasters express concern that there is no real way to monetize their content. On Twitch they can set up a Subscription to directly generate income from their viewers, but YouTube Gaming doesn't have a similar system.
And finally, they need to update apps on the game consoles. Lots of people broadcast to Twitch from the Xbox One and the Playstation 4. If YouTube wants to compete with Twitch it needs to give console gamers the tools to broadcast to YouTube. As well, they need YouTube Gaming apps on the consoles to supplement the existing YouTube apps.
So there's work to be done but again, I think they're off to a good start. Some of the broadcasts I've checked out have been really sharp; it might just be that 'new service smell' but it seems like YouTube Gaming is capable of delivering higher quality broadcasts than Twitch can. Don't take that as fact, it's just my subjective opinion based on watching a few streams. Definitely take a look and make up your own mind.