First off, this new launcher does away with the app drawer icon. The drawer itself remains, but it now hides under a "frosted glass" section along the static set of icons on the bottom of the homescreen, which have been increased in capacity to five as a result. To access the app drawer, you have two options. First, you can slide up anywhere in the "frosted" zone, including on the small arrow above the zone. Alternatively, you can just tap the arrow itself, which will instantly reveal the drawer. To close the drawer, you can swipe down from anywhere (except the notification and nav bars) or hit the back button. The new drawer has a large restyled search bar up top, but otherwise isn't especially different from the current Now launcher's.
Moving to the homescreen, we see that the standard Google Search widget has been removed. In its place is a calendar widget (this cannot be moved or removed), opposite of which you see what looks like a "G" pull-tab. Tapping the G launches search on the version of the launcher our sources showed us (this launcher is not running on final Nougat), but pulling it does nothing.
I've tried using the leaked Nexus/Pixel Launcher APK on my Nexus 6 a few times over the past couple days and my experience has been mixed. While I really like what they're doing with the app drawer, the new way to perform a Google search is clunky and less clear than the existing Google Now Launcher. While I think there's some work that can be done to make the top of the screen more useful, this doesn't help matters much in my opinion. Also, aesthetically, both the top button/tab and new look for app folders just don't look very good. I'm hoping, as they mention in the piece above, they add a little more stylistically to the button/tab before it's released.
Without question, the coolest part of the launcher is the new wallpaper app that leaked alongside it which features a ton of beautiful new (and constantly updated) background images. The app also includes the option to have your wallpaper automatically change after a period of time. It's really nice and just replaces the standard wallpaper fuction of the device and doesn't require the launcher to work.
I'm assuming this will all make more sense and work much better when (or if) the launcher arrives on Google's rumored Pixel devices in October. Until then, I can't see using this thing on my phone in its current state. If you want to give it a shot, you can grab the APKs for both the launcher and the wallpaper app here.