The WP store is a little more relaxed than the iOS app store - but - it still doesn't have any way to sideload any apps, which means it's still up to Microsoft, a single central entity, to decide what apps you can install on your device. The same is true for any Metro apps.

Does the WP SDK give you the ability to sideload apps?

At the very least, WP is different from iOS in that their SDK is provided for free (using the express edition of Visual Studio).

No it doesn't. You have to register your phone as one of three with your developer program account which is 79$ per year. The difference to iOS is that your phone is then unlocked for every other developers app signature.

Yeah, as far as I know, the Windows Phone Store certification policies are pretty lax (not sure if that’s reflected in their official terms or their implementation of them; I’m guessing it’s the latter). The only times I hear of apps being rejected or pulled seem to in cases of trademark infringement; and, even-then, only if the infringed-upon company requests them to do so..

I saw this play-out with Vimeo apps not too long ago. Prior to the company launching their (really nice btw) official app there were a few a third-party clients which used the Vimeo name and logo; since then, they've all rebranded or disappeared (I’m guessing at the request of Vimeo to avoid confusion).

Other than that, pretty much everything else seems to fly (I’m guessing security issues and serious bugs that come-up during review aside). This is all anecdotal (I don’t work at Microsoft or review apps for certification) but I’d be pretty shocked if they blocked an app like this.

Anyways, it looks pretty cool, maybe if iOS certification doesn’t go over the dev can port it to WP. For simpler apps (no offense here) I’ve heard it’s fairly quick work and involves a lot less on the testing/optimizing for 1,000+ device SKUs (Android) front.