The Android app can offer everything the iPhone one does -- barring the option to send barometric data to improve local reports -- but whether it does will depend on if you pay or not. While the iOS app is a $3.99 one-off purchase, Dark Sky on Android is a free app with a paid subscription option. For free, you get current conditions, a 24-hour forecast, a 7-day forecast and weather maps. So... it's basically any weather app.
If you're willing to pay $2.99 per year, you'll get access to the stuff that makes Dark Sky worth talking about in the first place: hyperlocal minute-by-minute forecasts, notifications and alerts. You'll also get something that iOS users won't: a weather widget for your home screen.
Dark Sky admits the pricing scheme is "a bit of an experiment." In order to win users over, it's offering a two-week free trial for the premium features, in the hope that they'll be hooked by the time it comes to actually paying.
There's one other thing worth remembering about Dark Sky: it's not a worldwide app. While it can offer basic forecasts for anywhere on the globe, its local reports are mostly restricted to the US, the UK, Ireland and parts of Canada and Australia. If you're not sure if you're covered, you can type your location into Dark Sky's Forecast site -- if you get a "local" tab, you're good to go.