I only charge my iPad once a month, because I so rarely use it. It's excellent as trans-oceanic plane entertainment, and as a portable video playing device around the house.

But it's far too heavy for general use. My Kindle is more on the level of how much weight I'm prepared to hold onto without support, unless I'm sitting in some very specific - and not very comfortable - configurations. At most times, including in bed, my phone (Galaxy Nexus) is a better device for the things that I might think of using an iPad for (primarily news snacking).