I also downloaded some APKs from other places and installed them, that is, apps that weren't coded specifically for the KF and they all worked. My only real complaint is sometimes the desktop screen doesn't respond to touches and you have to touch it again. Within apps there is no problem so I think it's a code problem with the Amazon desktop (launcher, bookcase, whatever it's called). The lack of a volume control is only a problem if you accidentally start playing something like a controversial podcast and the entire elevator or your office hears it! With my EVO I just turn the volume down within seconds. With the KF, yikes. I haven't had it happen yet thankfully.
Hang on guys. I got a Kindle Fire and I was able to install every app I normally use on my EVO except Skype and the Google Apps: That's 50 apps I was able to install that I've been using on my EVO. Remember, KF doesn't have bluetooth, GPS, accelerometer, 3G, cameras or a microphone (apparently if you plug in a headset that has a microphone, it works).
Yeah, "Developers have come out in force", for what 3 developers? That's a gross generalization. That being said, I have KF and it's got an amazingly bright screen that is great for games.