New Frontier was AMAZING right up until the timeskip for me. Everything from ATF onwards is fairly fun, but not a patch on the pre-timeskip books. Stone & Anvil, the last pre-timeskip book was absolutely superb.
Agreed. I hadn't read all the earlier ones, but found them enjoyable. However, "After the Fall" I thought was substandard and I couldn't get into the story one bit and didn't care for the new direction of the characters. I think I read 1 book after that, the title escapes me, but that was my last. The series had totally lost it's footing and IMHO never recovered.