I have both. Really it depends on which company you plan to support. You can sidleload the Kindle on your Nook Tablet w/o having to ruin your warranty or undo software. It was kind of pain, but it works fine. If you are really good with Android software, my understanding is you can put the Android store in. I figure I'm good with my Kindle and Amazon app store.

The Nook has more book settings to play with. You can have bookshelves, edit your library more, put a nice screen saver on(I have an animated fish tank) more fonts to choose from and nicer reading background colors to choose from. I can install movies via the SD card but you can't store them on the Nook. I have no desire to have Hulu+ or Netflix on my Nook as I don't care for either and don't want to pay every month to use it. If you have software that converts DVDs to a movie file even better. It was nice to download a movie of mine and watch it.

However; with the Kindle Fire, you can use Amazon's site to download/stream movies. Be warned, both tablets have terrible sound volume which sucks since they support movies and audio books. Bad decision on their part.

The Fire is pretty basic. You have no bookshelves so you endlessly turn the carousel to find the book or use your search. You can either have the book on or archive it. You are stuck with an ugly bookcase for the background with oversized icons of your books/apps. It's pretty basic.

Both load the internet fast and browsing is easy. I think the Fire's touchscreen is more responsive so I tend to use the internet more on it. The colors are nice on both, but I think the Nook has more vivid looking ones.

Battery life on both is just fine.

You can't go wrong with either one. If you are more of a detailed book reader and want more editing options, the Nook is probably the better choice. If you want simple and quick, the Fire is the way to go.