The ONE test you want to do on these tablets is
To see if your web sites work on them. While the Kindle Fire HD is really really great some will not like that some sites don't work. CNET Videos are fine but no videos at Yahoo Finance work. Go figure?
The KF HD is again, really really great for the buck. Still getting the Nexus for another reason. I'm lucky that the office is on the move to Android apps so we are getting more units.