Journeyed there and back again
This is one of the ones I was looking at actually but the " Only Simon, a lowly castle scullion" in the description put me off. It made it seem like a typical farm boy discovers he is superman kinda thing, like the Belgariad, not that that's bad thing it's just I have read tons of that sort of thing. Could you compare it to anything? How is Tad Williams writing style??
As a writer, Tad Williams probably has similar prose to Brandon Sanderson. He's somewhere between Sanderson and Jordan, tending more toward the former. I personally think he's better as a prose writer than Sanderson (I don't mentally second-guess his prose choices while I read), but not with dialogue. Honestly, I find them pretty similar though. As similar as two individual, talented people can be. Understand that I'm not a madcap fantasy reader who devours everything in the genre though, so that is simply the best comparison that comes to mind.
As a side note, if you start the series, the first book takes awhile to pick up. It took me awhile to get through the first half, and then almost no time to get through the second (incidentally, this is exactly how I did Way of Kings as well).