As a developer, I've had horrible, horrible experiences with the Amazon Appstore that will keep me away for many months yet; with apps being rejected and moved through all stages of the feedback process without so much as a whimper of feedback from Amazon. Genuinely the worst "customer" experience I can recall.

Unfortunately, it may not be developers who decide which one succeeds. If Amazon becomes the place where the money is, then there will be no avoiding it by developers.