Apolyton's Solver has written a great review of Dark Avatar. He concludes with giving DA a very solid 9.2.

"In the end, I give Dark Avatar a score of 9.2 out of 10 for delivering much more than most expansion packs do. Dark Avatar’s positives truly more than make up for the negatives, and it’s a must-have for everyone who played GalCiv2 and at least somewhat enjoyed it."

The review touches all of the new aspects that DA brought to GalCiv 2. And clearly Solver had been playing quite a few games before he wrote down his findings.

There's also a lot of constructive criticism in the review. A lot of which could help Brad and his team to improve DA even further.