We got our daughter a Kindle Fire HD for her 12th birthday. So far its a fantastic fit for her needs: enough available games to keep her happy, access to Netflix and her videos and music. The latter two are a little clumsy (certainly not iTunes-caliber), but so far the differences don't seem like a big deal to her. At the end of the day you always end up manually ending space on these devices, and iTunes doesn't help that process much.
The one really confusing thing is how to get your own videos onto it. We have Handbrake'd a lot of our DVD's for the iPad, and my daughter wanted these on her Fire. There are lots of hints for older Kindle Fires, but none of them proved useful. Here's what you need to do (sorry, Mac only; some of this may be useful on Windows):
Install a copy of Android File Transfer on your Mac.
Hook up your Kindle via USB and open Android File Transfer.
Drag any iPad compatible to the Movies folder on the Kindle. So far any .mp4 and .m4v files have worked fine.
Launch the Personal Videos app (you might have to search for it to find it). The videos will not show up in the standard Videos app, only in the Personal Videos app.
The screen on the HD looks fantastic!
Note that this only works for files which are not encumbered by digital rights management (DRM) of some system or vendor. If you bought a song or movie on iTunes or other you'll have to do some additional work to get a version that the Fire will recognize.