We've had the Galaxy Tab 2 for a few months and love it. I have no experience with the Kindle Fire to compare, though.
I think our only complaint so far has been that the internal antenna doesn't seem to be as sensitive as our other hand held devices. Sometimes I lose the wifi connection when I'm across the house from our router. It's not totally predictable and moving a little to the left or right solves it, and then I can move back to where I was. Kind of annoying if I'm in bed and don't really want to get up and move around to get a signal. Again, I don't have a kindle so I'm not sure how that compares, but I know with our laptop, phones and itouch that isn't ever an issue.