This codex is essentially a lot a little tweaks all over the place. It really is worth reading through it properly, most of the interwebs seem to be unaware that hits from Instant Death reduce your Reanimation roll by 1 for example.
Overall though it's a good book. I think I'll use the Decurion Detachment quite a bit seeing as what I typically put into an army is what is in just the Reclamation Legion. Although I do now need £48 for Tomb Blades and Reaver Jet Bikes so I can kit bash them together. I'm also going to get some more Warriors and use Power Claw/Lightening Claw blades and some Greenstuff to convert them into Flayed Ones. 20 Flayed ones with a Chronometron Cryptek in there for 350 points and just run them into whaever the hell I want to die. Should be fun if nothing else.
Typically what I'm seeing with this book is that where something gets a nerf it also gets a boost. Take the Doom Scythe for example. One player I know who goes to lots of tournaments was saying how they are crap and not worth taking now. However they are 15 points cheaper and instead of a line it's a blast with Lance. I prefer this version. When you fired at tanks before you were typically only hitting 1, maybe 2 anyway. So you'll probably still hit the same number of tanks but now in a worst case scenario you are glancing on a 2+, penning on a 3+. In terms of infantry killing you're probably going to be getting about the same number of models as you were before unless you only played complete idiots who run their units around in straight lines. So it got the "nerf" of no longer auto-hitting but gained Lance and a points reduction.
The only thing that bugs me is that when the Monolith fires its Whip the Flux Arcs can only Snap Fire still. Other than that I'm loving it and can't wait to start using it on the table top.