The problem with these plans are the data caps. Who cares if you can hit 12Mbps when you have a 2 or 5GB cap?. I would love to have something like this tethered to my network and combine my phone/internet data, but streaming videos just eats bandwidth way too fast. When I was watch HD tv shows I was streaming over 1TB per month. Now that I am watching more SD content it isn't quite that bad, but it is still well over 250GB/mo (keep in mind this is with 3 people getting all of their TV show through the internet as we do not have cable, I don't think I have the free time to eat all of that bandwidth myself). Not to mention the high ping rate on 3/4G networks compared to everything else, but as I rarely game online that really isn't a pressing issue.
But anyways, remove the data cap and tethering fees and I would move on over to the smartphone age in a heartbeat. For now I will stick with my little nokia brick that simply makes phone calls.