Witchfinder General said:
If you've read the books you'd agree.
I've read the entire trilogy, multiple times (he's one of my favourite recent sf authors), and i agree with the "umm, what?" comment. In fact, i can barely see any similarities at all (beyond basic SF staples like the existence of humans and aliens, and FTL travel...). Unless there's a secret sidequest that reveals a subplot involving the reincarnation of human souls from purgatory who then attempt to take over the galaxy, anyway.
I'd be far more inclined to point to similarities with David Brin's Uplift saga (humanity as a newcomer to an established multi-species galactic civilization; it's even mentioned briefly that the Krogan were 'uplifted' by the Salarians, which i thought was a nice nod to an obvious influence), along with Alastair Reynolds' Revelation Space series (ancient machine race periodically wiping out advanced civilizations; although the concept was hardly original when he wrote about it).
Overall i'd say they've done an excellent job of creating their own, reasonably unique SF universe, though. Most of the elements have been done before in SF literature (the same could be said for most SF stories, though; truly original ideas are few and far between), but it's a fantastically well-executed combination.