I found this book a fitting end to both the series which chart the progress of Garion from boyhood to his destiny. In response to the adverse comments I have heard / read, I would like to point out that by the time you reached the start of this book, you have already read 9 books, so something genuine must have kept you reading till the end.
If you read the first book of the Belgariad, you have a pretty good idea of the style and content of the other 9 books. This isn't a negative comment, just a reassurance that the same attention to detail remains throughout both series.
As a "final" book, the Seeress of Kell draws together all the loose ends in a way which makes you marvel that someone could keep a plot going (with all the new developments) over the years which it took David (and Leigh Eddings) to write the series.
For people who have only just come to this series and loved it, spare a thought for those of us who had to wait for several years between the publishing of the Seeress of Kell and the Prequels "Belgarath, the sorcerer" and ultimately "Polgara"!
The only negative criticism I would raise (and it applies more to the prequel novels than this)is that for a fantasy series set in an imaged world the speech is far too American!
If being a well-paced, descriptive, and full (but uncluttered) novel makes it childish, then I will happily turn my attention to the children's corner in future!