Unfortunately, I tend to get most of my apps from Google Play.
I *LIKE* the concept that the Amazon App Store has, in that they vet the apps a bit more, and attempt to stop bad apps/scammers/etc from being able to place their apps on their site.
However, in practice, this just ends up leading to Amazon always being behind in updates for any specific app, sometimes many versions behind.
There are countless apps that I have gotten from Amazon, that are multiple versions behind compared to their counterparts on Google Play.
I don't know whether Amazon is just far behind in approving the updates, or whether the app writers just simply give up submitting the updates to Amazon, whether they forget, or whether they just don't care.
In any case, in the end, I do what I have to do to be on the current stuff, which usually means getting my apps from Google Play.