I read the first two books when they were published, and have just finished this one. I'll confess to not clearly remembering everything from before, as I was reading another fantasy trilogies with a remarkably similar background at the same time (the rather excellent Raven's Shadow by Anthony Ryan). However, I have to say that I have enjoyed this series, and someone picking up this book without having read the previous two wouldn't be at a great disadvantage.
What I liked: lots of little twists that made this series unique: rapier/epée based swordsmanship, an interesting, but mostly ignored, magic system, and the banking system. It wasn't really mentioned, but gunpowder, guns and cannons aren't present, nor are heavy two handers and the related plate armour. There's some thought behind that, but it hasn't been shown to us. A nice touch.
The first book (The Tattered Banner) was by far the strongest of the trilogy. It flowed, and had a certain joy in the writing that compelled me to read it, and I allowed that momentum to carry me through the rest. Both the second and the third books were rather episodic, as if the author didn't really have the heart to finish what he had started. This was apparent in a change in style, and not really reusing familiar characters from the first. In fact, only Soren and Amero from the first book play more than cursory roles in this, with a new character taking up many of the pages, and being really the principal actor in the story.
Despite this, I enjoyed the series, and would recommend it (certainly the first).