Battery life is probably the biggest drawback to tablets. My wife has a Kobo and I use my Samsung Galaxy Note for reading.
The Note is awesome because it is always with me, but if I travel and can't plugin I have to be cautious. If I read too many movies, surf the web, listen to music and read on my Note, then there may not be enough power to make calls when I need it.
Not really an issue for me often at home, but an issue when travelling.
This new technology would help.