Contrary to the unjustified opinions of some reviews of this series of books, I believe this sequel to the Elenium is a strong example of Edding's powerful fantasy fiction.
Firstly - don't read this if you haven't read the Elenium! Of course you are going to find it difficult to engage with the characters if you enter the series after all the exposition has been accomplished. Also, as a sequel, you have to expect that the "bad guys" are going to be somewhat less straightforward than those of the first series, who were unsurprisingly defeated at the end of the Elenium.
Next - don't complain about it being similar (okay, very similar) to the Elenium/Belgariad/Mallorean. From the blurb you can tell that it's going to be about a quest (fairly standard for fantasy fiction) to rid the world of evil (sound familiar to anyone?). There are only a certain number of ways to accomplish this, namely by killing the evil involved. The real strength of Edding's writing is in the detail and dialogue of the story, not necessarily the unpredictable plotline.
One of the problems with The Tamuli is that when Eddings and his wife were creating the world, it was done so in a much shorter time than that of the Belgariad. This has led to a lack of depth in some areas, but by no means is it a superficial world. The cultures are all developed beyond those you will find in many books, there's no use of typical "monster" sterotypes, since the Trolls and Ogres of this world have been portrayed as more intelligent than most.
To those who find the characters to be "dull" or "unimaginative" I say that the range of different personalities is enough to keep most people interested. The presence of Aphrael throughout is somewhat irritating I'll admit - the Child-Goddess takes a lot of the threat elements in any fight situations.
The inclusion of political elements in this book pushes it above the more recent works of the Eddings, namely The Redemption of Althalus and the Dreamers, where the more adult themes are removed due to the more primitive societies in which the books are set. The Tamuli encourages the reader to see a conflict across all layers of the Daresian continent, and one that engulfs all citizens of the world of the Elenium and Tamuli.
The climax to the series is fulfilling, whilst perhaps lacking the emotional resonance of the Mallorean, which is to be expected as it is the culmination of only six books, rather than ten.
In conclusion, if you're new to Eddings, read the Belgariad first. It's still his best work. If you've read that, and the Mallorean, then read the Elenium! Again, that is a superior example of storytelling. Only then should you tackle this series of novels.