Not a terrible idea probably, but sophisticated users might be put off by the popup signup.
I don't care enough yet about your service to give you my personal information OR to even bother disabling Javascript which I assume defeats the popup.
Personally I find that kind of experience intrusive.
I do like the idea though, but what happens after?
Do I get to keep the app? Do I get upgrades to an app?
I take it the users who are early adopters are also free testers to some degree.
Popup seems to be missing a close button, so I can not even see what kind of apps you deem to be "premium". Also the word "premium" lights a red light in my brain that means "scam".
Not saying you are a scammer, just saying what my internal bayesian classifier has learned about "premium".
I'm not exactly sure why it's not simply iPhone vs Android. It's not like "HTC" and "Samsung" often have apps that will work on one but not the other. At first I didn't even realize that you did have Android apps, because "Motorola" can be older java-based phones, "Nokia" can be a black and white flip-phone... Not exactly obvious at first glance.
So yeah, just say "iPhone" "iPad" and "Android". Hell, remove the drop-down and make it a logo that you select instead, that should be even easier.
I don't care enough yet about your service to give you my personal information OR to even bother disabling Javascript which I assume defeats the popup.
Let me poke around without signing anything.