I haven't read all of the titles on your list but I will comment on a few of them...
Helsreach- Simply put, one of my all time favorite loyalist SM books. I am a huge fan of ADB's writing style and I think he does a great job of delivering the grimness one should expect from Warhammer with a twist of humor here and there. His characters are rarely dull.
Deliverance Lost- Horrible. Gav Thorpe is one of the worst writers BL has. He focuses on pointless minutia to draw out already dull scenes in an effort to pump life into writing. His characters are flat and uninteresting and many of his ideas border on the ridiculous. I have sworn off buying another book of his.
Fear to Tread- I have to agree that this is not a great book. I wanted to like it since the Blood Angels are my favorite chapter but it just isn't well written. The characters are uninteresting and then there is the whole marines fighting inanimate objects thing that is just silly in my opinion. Swallow has been a stain on my beloved chapter and although this book is better than his previous BA efforts it still falls very short.
Angel Exterminatus- I liked the book quite a bit. As many have stated the portrayal of Perturabo is very good. The story is also interesting and well written.
Legion- This is also another of my favorites in the HH series. Some aspects may be sort of a leap of logic but that is the way it has been in many of the HH books. In my opinion the primarchs are far too easily swayed to heresy.
Gildar Rift- It was okay, not great but not bad either. I wouldn't put it as a high priority but if at some point down it may be worth a read. You may enjoy it more than I did.