This is one of those books that's fun to read, but has little else going for it. If you're a hardcore fantasy fan looking to kill some time, you could do worse, but in general I would not recommend.
Lion of Senet is an unusual epic fantasy in that not only is it decidedly not a Tolkien knock-off--no orcs or elves in sight--but there's no magic, no drawn-out journeys and no epic battles. Instead, the plot is driven by political manuevering (perhaps better termed "interpersonal manipulation"), and the primary conflict is between science and religion. Although it feels like fantasy, the book has been termed science fiction due to the setting, a world with two suns. Consequently, it's never truly dark, except when one sun eclipses the other: a phenomenon that provides the basis for the villainous sham religion. (Oddly, given that the book prizes science and math, this orbit makes no sense; one could argue that that's the real fantasy element.)
In other ways, it's a fairly traditional tale of a unusually talented teenage boy, raised in obscurity, who's secretly the heir to a kingdom and spends the story making friends and learning about his mysterious parentage and about how to play politics. You've all read that before, but the plot is actually the best thing about the book. It's well-paced, moving briskly from one character to the next, and kept me turning pages--in fact, I read more than half of the book in one day. The problem is that it depends heavily on melodrama: people overhearing things they shouldn't, often when someone is bluntly explaining something that either shouldn't need be said or realistically wouldn't be, people being easily manipulated, people having simplistic emotional responses to events, and so on.
As for the characters, there's just not much there. The book fails at the crucial task of making them seem like real, believable human beings, rather than simply words on a page. The women are particularly bad, being almost uniformly one-dimensional (the possible exception is Alenor, who joins the men in two-dimensionality--still not good). While the author avoids the most common reasons for flat female characters--they aren't defined as sex objects or by relationships with men--the book isn't free of unfortunate tropes, either. There are three types of women here: the virgins, who are good (if often annoying, prone to yelling at people who are saving their lives and so on); the mothers, who are embarrassingly useless and unable to control their emotions, even when they're queens; and the whores, who are all diagnosable psychopaths running the scam religion.
Even aside from the problematic implications, though, the characters simply lack substance. It's the sort of book where you can pinpoint the main villain the moment she appears because all she ever thinks about is how she wants power over everyone and doesn't care who she kills in the process. Subtle, that.
The writing isn't much good either, although I've certainly seen worse. It has a tendency to be repetitive, overuse adverbs, and state the obvious (repeatedly). And there are the jarringly modern idioms in the dialogue: "be like that," "just a tad," "what's your problem?" and the like. Some of the exposition is clumsy as well, with the main character impossibly ignorant of basic facts about his own world. As for the world itself, it's passable, but we never learn much about the place except that it's a garden-variety quasi-medieval type and has an abundance of natural disasters.
In the end, this was a somewhat amusing book, but a fairly poorly-written one that I would not recommend. I was entertained enough to finish, but although there's little resolution, I'm unlikely to pick up the sequel.