... although the last time is many years ago. I must reread, absolutely right Rebekah. It was one of the very first genre books I ever read. Bought in a Dutch translation around 1991-1992, for almost nothing. You could find almost nothing from this genre in the Netherlands back then, and wasn't bought either (which is why I think I paid less than EUR 2 today's money for the hard cover edition). So when I saw this (for that price) I bought it, fell in love with it and was hooked to the genre ever since.
This book is my puberty infatuation.
I was pleasantly surprised at the sympathy I got for Brandin (especially when I reread), which made it more believable that all is not black and white. It did make me wonder why we didn't get more positive view from the other side of the hate-triangle, namely Alberico. All I remember is that he's supposed to be a "Hitler with magic" (or more accurately: "Rommel with magic"?). No shades of grey there, just "get rid of him". It made the struggle slightly less interesting.
One thing that you didn't mention, but that I thought was interesting, was the link between Tigana and the "Fionavar Tapestry", which he had written before. In Tigana, Brandin mentions the Tapestry as a legend he learned as a child, about many worlds, one of which was Fionavar. I think other books by Kay also mention the Tapestry, which ties them together somewhat.
The ending, especially the Dianora-<deleted spoiler> one, was emotionally heavy for me, but partly because I was quite young when I first read this.