@Bane122: I think Cryptum was more interesting for Halo fans; it revealed a lot more backstory. I just found Primordium to be a better story altogether. The characters have a goal, they are motivated and take action.
I definitely get your point that the characters basically just walk the whole book (it's the Lord of the Rings of the Halo franchise), but that's basically all that happened in Cryptum. That's the thing I've found disappointing about this trilogy so far, the first 2/3rds of both books consisted of the main characters roaming around until the antagonists got around to doing something in the last bit of the book.
Considering how much they are implying or revealing, though, I'm definitely excited about Silentium, since it's the first one to come out since Halo 4 released and will almost definitely give us some insight into Halo 5.
I kind of like Bear's hard sci-fi, I just there was a bit more character-motivated action throughout. Guilty Spark's narration to ONI did a lot to keep me going though.