Well, I'm 2 for 2 with this one--two failures.
I figured I could expect apps from getjar to work on the Vox, since the Get Apps app on the Vox takes me to getjar. They had the Good e-Reader App store app, from which one could download other apps.
From the Good e-Reader app store, I downloaded and installed Google Books for Android. It installed, but it wouldn't work beyond the first screen. I was not able to link it to an account because the app was simply frozen. So I uninstalled it.
I see the Good e-Reader app store offered a Kindle app newer than the one I have on my Vox, which is I think a version 1.x and working just fine. I recently purchased a Kindle book (Kobo didn't have it) and it's a great book and I'm right in the middle of it...I downloaded and installed the newer Kindle app. It crashed relentlessly on the Vox. I ended up reinstalling the old Kindle app. I lost my bookmark, but otherwise things are fine.
I don't know if it's just me, or if other people have downloaded apps from the Good e-Reader store and they're working fine on the Vox. I just thought I would provide my experience as a heads up. I don't think I'll try again. In fact, I think I may as well uninstall the Good e-Reader app.