Custom ROMs on Kindle Fires

Hey all, I remember with the original Kindle Fire it was possible to put CyanogenMod 7 on there. I have been out of the loop (and have never owned a Kindle Fire). How has the 3rd party development been for the Kindle Fires since then?

I had a Notion Ink Adam and a HP Touchpad, so I know what it is like when custom Android ROMs are being hacked onto devices that originally ran something less than similar to stock Android / CM.

With the new HDX announcements, I am wondering what the expected 3rd party support will be, based on what the response was for previous models.

Furthermore, how was the experience with custom ROMs? Was it a flawless experience, great with a few things left buggy, or the horror that was the first attempts to get CM on the HP Touchpad?

Of course, Don't get an HDX today if the only way you won't like Amazon's software offerings. In the past have made the mistake of buying things on the promise of updates. Just look at the Motorolla Xoom's LTE support, or the Ouya overgrown imagination. Buy products for what they can do today, not what you think you can do later.