I really like this game - it has a strong theme, great production (I love the little coloured lacquer pieces) and is a good price considering its size and what you get.
My group finds it to be snappier than Twilight Imperium which was our previous day-long strategy game. It can run to about 6 hours (so it is a bit snappier than TI) with the full player count but I don't find it drags too badly. You can always be doing something like discussing the current battle with a neighbour or something.
One thing I really like is that it doesn't have any dice component - the battles are all done on who can bring to bear the highest strength. If you do want an element of chance they include an optional module called Tides of Battle which works quite nicely.
I would caution that the game does not work quite as well with low player counts of 3 or 4. That being said, if you are prepared to shell out for the recent Mother of Dragons expansion, that fixes this issue and brings a lot of other improvements besides.
I would recommend this game to anyone who likes longer strategy games like TI or Axis and Allies, or to any die hard Game of Thrones fans because it really captures its theme well!