I quite enjoyed the read, mostly because it was good to get back in Ender's head and watch him run mental circles around bad people! There's something very gratifying about seeing a good character who's much smarter than everyone else going to town on bad guys.
The book fills in a lot of holes, and not just temporal ones. It explains how Ender lives so long through the rest of the series (because normal relativistic travel couldn't account for the time), why Valentine joins him for the rest of his life, and why he never returns to Earth.
My favorite parts, of course, were the descriptions of the ships and how they work. Definitely a sci-fi nerd! But of course all the mental circles were fun too - seeing Ender tricking people. etc.
Overall, if you are a fan of Ender's Game then I imagine you'll enjoy Ender in Exile, even if you didn't enjoy Speaker for the Dead.