So, I've built a Windows Store App that's now in the store. It's a sort of front-end for an online retailer (bol.com) in the Netherlands. Basically, you can browse and search the catalog, add it to your cart, and buy stuff. It also provides videos like trailers, interviews, song samples etc. that the retailer itself doesn't have, just to sort of provide some extra value.
All in all I have to say that the whole thing went pretty smooth. Most of the frustration was down to the retailer's api and its peculiar design choices (an HTTP 404 error when no products are found? Really?), though some of it was down to weird control behavior. The FlipView needs some definite work. It always briefly shows the first item in a collection before switching to the item you specified, which causes all sorts of pain. Also, setting up settings Flyouts is way more hassle than it should be. Fortunately the Callisto toolkit has a great control for that.
What I'm impressed with is with how smooth it all looks and how little time that took me. Stuff like items being added and removed to a shopping cart all happens with these little animations that are built in. It's not that these things weren't possible before, but it would probably (and regrettably) have been such a low priority that it never would've happened. Now it's there for free. My favorite feature is syncing the shopping cart across PC's: I can add a bunch of stuff to my cart on the desktop and it'll magically show up on the laptop as well. This was a simple matter of saving the shopping cart data in a roaming folder and reloading it when a certain event was fired. Five lines of code. Sweet. Not bad for a framework that, according to some, only supports RSS and fart apps.
The app should be available worldwide, but it's only available in Dutch for now. Partly because 99% of the target audience speaks Dutch, and partly because the English version I provided got rejected in the certification process. Some of the text comes directly from the retailer's api, and that's always in Dutch, so you get a weird mix that the approval people presumably didn't like.
If you want to give it a go, feel free: http://apps.microsoft.com/webpdp/nl-NL/app/wubbo/c3d1142d-2a9c-4ba1-a851-dc005348c702 Even if you don't understand Dutch, you can play around with it, though. Just try clicking on a bunch of stuff and dragging product images to the cart. You need an account to actually buy stuff, so you won't accidentally get charged anything. Let me know what you think, and if you do try it, please leave a rating.
Edit: or just watch the video. But seriously, downloading and rating it is better.