If Amazon are going to maintain an Android fork, I wonder how well Android apps will be able to play with it. It would be a huge disappointment if 2.2+ apps were unavailable (or installing Google Market for that matter). I can see why Amazon has gone down this path, but I do wonder if it's the right thing, rather than doing everyone's favorite/most hated carrier-specific bolt-ons instead. I also hope that Amazon does…
If any API incompatibilities emerge (beyond the normal API level that Android uses to distinguish between release APIs) then developers will be forced to fork their own products and maintain 2 separate release channels -- one for the Android market and one for the Kindle market.
Beyond that, Android will continue to fly ahead with each release and the Kindle won't be able to keep up without significant time pulling and merging changes from upstream. I'm not looking forward to continually only having access to last years apps because the Kindle is a year behind the mainline Android release.
Unless Amazon goes through the Android certification process, and keeps their "fork" as a pure UI modification, I'm going to pass on this. It might be bright and shiny on day 1, but on day 365 it could be a different story.