YES it is. And we'll tell you how do we know.
When the first UFHO was launched on the web, we played it extensively with dozens of players around the world. We know that the game is fun, and the more fun if played with someone you know.
It gives great satisfaction to be able to overcome your opponent thanks to your smart thinking, and unlike chess everything is quicker and fast-paced, so the action is more frantic overall.
And if you still don't believe us, try a very early demo:
http://dl.dropbox.com/u/4245674/UFHO2-DemoPC.zip | http://dl.dropbox.com/u/4245674/UFHO2-DemoMac.zip