For the first time I went into this challenge full of enthusiasm. The first few chapters of the book were a tad confusing as they referenced an earlier series which I haven't read (Will be getting onto them now though). I gradually figured out what had happened, and from there on in I enjoyed the book immensely. I think I might have gotten more out of it if I had read the books before it, but they really aren't necessary.
I can't really compare this book too much to The Way of Shadows, as they are fairly different; TWoS is far more action-y, whereas The Ambassador's Mission focuses more on the politics (Well hello, 'Ambassador's Mission'?) and intrigue.
I would definitely read this again, probably after I have read the earlier series. After which I'd read the books which immediately follow it - as much as I want to go straight to them (Cliffhangers #rage) - I think I'd enjoy them more after I know all of the back story.