This seemed a little weak to me. Thinking about stories of revenge, (I tweeted about IMO the 2 greatest stories of revenge: "The Count of Monte Cristo", by Dumas, and "The Stars My Destination", by Bester) I couldn't really think of any where the person seeking revenge was not seeking it for harm done to themselves. Dedicating one's life to avenge a wrong to one's parent seemed far fetched to me. But, if you go to Japanese or Chinese stories, you could probably find a fair number of instances. So I guess that the authors had Japanese or Chinese influences.
The exciting conclusion is maybe a little unexpected from the previous thrust of the books, and way over the top, but still, there's a lot of that that goes around in science fiction. I think the conclusion worked, and was somewhat inspirational.
So if you like space opera, I would recommend this trilogy. It definitely sucks you in and keeps you turning pages.