I just wanted to update and thank everyone for their help and input. We ended up going with Kindles. It mostly came down to potential accessibility from oversees and it just seemed the Kindle was a safer bet in that respects compared to the Nook. The Sony was still a high contender but my husband didn't really like the 5" screen once we got a chance to see it in the store and the bigger Sonys were too big of a price jump to justify them for the kids.
Unfortunately, the two places we looked in town were sold out of stock on the Kindles so we had to order them..... now I can't wait to get my hands on them (I'm pretty sure I know what I'll be putting on my Christmas wish list this year
).
Thanks!