It is very rare to finish a series with satisfaction, especially a long-running one. I remember being furious enough with C.S. Lewis's Narnia series that I threw the final book across the room. (I was ten.) The end of the Harry Potter series upset me enough that I didn't read it again for over a year. (I'm not saying how old I was but at least I didn't throw it.) I was disappointed with the end of Jessica Anderson's Nightwatcher series since I felt her chosen ending undermined the initial premise ... and I'm convinced there was material published elsewhere which I never saw which might have explained just what was going on. And don't get me started on television shows.
But I think Memory of Light wrapped up the Wheel of Time series almost perfectly. Characters did die, but given that the plot revolves around an epic battle between ultimate good and ultimate evil, that was to be expected. Most importantly, each death felt as if it meant something. No one died in vain.
There were no loose ends. No unresolved plots. Which given that the series ran to almost 17 thousand pages with over 20 major characters is darn impressive.
Finally, the ending made sense. It was clear why they'd had to spend so much time getting to this particular finale. There was lots of meaningful character growth and none of them got out without accumulating a few scars along the way. That is believable and makes some of the more unpleasant plot points acceptable, at least to me.
I'm glad I stuck with it.