This is a good thick book and promises sequels the same. That isn't my only requirement in an escapist fantasy novel, but it certainly doesn't hurt. Next requirement met: lots happens. Humor! Pathos! Battles! Seductions good and bad! Spirit quests! Third requirement: worldbuilding: in this case, done by picking up Mongol society of the Golden Horde era and transplanting it to its more-and-better-besides world; real magic, two suns, several moons. Exotic societies that the Greeks described far to their east are exotic societies far to the west; nice touch.
I think there could have been more attention paid to material existence, especially of the common people, especially of all the work it takes to have such enormous horse herds ready to ride. On the other hand, the best food anyone eats is mutton-fat, and one of the risks of riding is getting trapped under a fallen horse, so the details convinced me even if they weren't filled in.
What does fill in many and many pages, and I liked a lot, is parallel scenes in the adventures of all the minor characters. This avoids the token-collecting feeling that bad versions of the Heroic Quest so often provide ("Tius-dag, loyal retainer of demented ruler, one secret, one shiny button, check, g'bye"). It also fills out what I thought was the moral problem of the novel: how an absolute ruler with power held by the somewhat-violent election of his underlings balances doing honor to those underlings, but not empowering them enough to make them rivals, or thwarting them enough to make them rivals. Most of the good and bad decisions in this story turn on that problem.
There are also demons and a frog princess. The prince is buffeted by events, but he seems to have had a lengthy previous series to recover from.
The failing of the whole is the writing. At best, it's flatly descriptive. This is okay when lots happens. There are too many contemporary turns of phrase, especially 'thing' for any complicated emotional shock. Finally, the proofreading is abysmal, with terrible typos and unmatched double-quotation marks.
ISBN: 0756401976
So wrote clew in SF&F.