If you're looking to run Android apps, an Android device is really your best option.
While a full Windows device (Surface Pro and most Windows tablets apart from the RT/Surface 2) will let you run an Android emulator, you'll get better results with a device meant to run Android.
Personally, I found the RT to be the best ARM-based tablet I've ever used, but that was because I found what it could do (that other tablets couldn't) far outweighed the "missing" apps for me.