I had a BlackBerry Z10 and the central problem with that approach to running Android apps was that only free apps were really legit, because of the inability to access the Google Play Store to buy paid apps. Hopefully Jolla will come up with a solution, preferably one that allows you to take apps directly from your Android device or somehow access the stuff you've already bought. The third party store solutions mentioned by Jolla sound interesting

The second problem is the frequent update cycle of the Android versions and the apps that it runs. Keeping up with Google is no easy task. And if you haven't been on an Android device lately, the pace of development is unbelievably fast compared to Meego/Maemo/most anything else. Every day I have several apps updating on my Android device (HTC One). Jolla has to hit Android compatibility out of the park, because the quality, variety, and availability of apps simply will not be enough without the addition of Android apps.

I, for one, would be super happy with a Jolla phone with great Android compatibility, but with the great Sailfish OS UI, more openness, unique styling, and well, something a little more Unlike that's great for single handed use.