Added the KF to a household with a couple of Android smartphones, five Windows computers, and an iPad 2. I'm very familiar with Android phones going back to the original Droid. And while I like Android environment very much, I was looking for a device that like the iPad that required virtually no management and maintenance. (I already have enough tech stuff to "manage.")
In other words, unlike many of the folks on this board, I suspect, I wasn't looking for a highly customizable user experience, much less a rootable device. I just wanted it to work well for all the members of my family including my technophobic spouse and my seven year old daughter.
Overall, it has been a huge success. Other than hating the fact that I have to clear the damn carousel on a regular basis, it's easy as pie to use and requires virtually NO maintenance. Even better, a free app called "Kids Place" enables me to create a set of enabled apps for my daughter without worrying that she'll either accidentally mess up the settings on the KF or that we'll find a refrigerator being delivered to our door unexpectedly. That level of control, by the way, is missing on the iPad.
Furthermore, although the screen is smaller than the iPad's the KF's 16x9 aspect ratio actually works better for viewing movies. (Though not for content creation.) Add the "free" movies, books, apps and other perks of "Prime" membership at a slightly over $6 a month and it's a no brainer.
Bottom line is that I can't comment on the "hackability" of the KF though it appears to be easily hackable. But as a device that has about 80% of the functionality of an iPad at 40% of the price, it's a winner.