In practice, Street View works well even on older Android devices, so it should have no problem on high-end Androids or, obviously, the iPhone or iPad.
The feature is universal, i.e. it works on all platforms, and this is the beauty of building on the web, but everyone knows why Google rolled it out now, it's because the native Google Maps app, Street View and all, was kicked out of iOS 6.
If that hadn't happened, Google had no incentive to build Street View into the mobile site, those who wanted it could simply install the app for their Android or iOS device.
But, while Google works on its own native app for iOS, it needed to beef up the mobile version of Google Maps. Given that there's a chance Google Maps won't even be allowed in the App Store, the site could be crucial for Google on iOS devices.
Using Street View on a mobile device is simple enough, just search for a location and then click on the Pegman icon. There's no way of enabling the feature without searching for a location first. You'll be taken to a new tab, separate from the Maps one you were already using.
If you're unfortunate enough to be stuck with iOS 6, you can at least create a shortcut to the Google Maps site on your home screen.