Charlie - I've been thrashing around for a tablet to use at work and on the road when traveling vs carrying my laptop. I'm not very interested in using it for watching movies or even reading books, but for taking work notes and surfing the web, etc.
One of my big gripes with these tablets has been their inability (as I understand it) to simply work with a PC. For example - I'd like to tether to my cell phone for internet vs buying another 4G package, have a USB port to plug in my printer, I'd like to be able to use Word, Excel back and forth between the PC and tablet. Not sure any of the tablets on the market today can do these chores - yet. However, I looked at a Microsoft Surface tablet and they look pretty slick - but, there are two versions. One is released and is Windows 8 RT software driven and the other model, soon to be released has full blown Windows 8. The windows 8 tablet (as I understand it) can operate like a PC and is compatible it sounds like in every way. So loading similar programs and plugging into printers, etc. should be easy to do.
All of this may be more $$$'s than you are looking to spend, including an ipad.
I don't have a tablet yet, but have had the ipad on my radar - though almost everyone at work and family who is tuned-in with these things from an IT standpoint doesn't like the ipad. They speak of the ipad as being overly restricted by Apple in what you can do with them and what apps you can run.
I like the ipad because it's simple to use, has a gazillion apps and like my washing machine, you turn it on and it simply works - not a lot of complicated crap to wrestle with.
Back to your original question. I asked our IT guy here at work who recently bought a couple of Kindle Fire tablets for his kids his opinion. I asked him why kindle vs the Nook and he simply said personal preference. But he gave me an interesting link to a review of these tablets and how they compare. Here's the link:
http://news.cnet.com/8301-17938_105-20009738-1/kindle-vs-nook-vs-ipad-which-e-book-reader-should-you-buy/
Hope this helps....