For the Blood Angels, this answer is yes. Of course, they didn't have far to go in that regards. For me, the rules are important, but not quite as important as the models. Oh sure, a crappy book can absolutely ruin a good range of miniatures through outright awful rules.* So can simply lagging behind new design trends. But, I really need to choose an army I actually want to spend time painting. Take the Eldar, for example. Sure there are really only one, maybe two (depending on you definitions), competitive builds in their codex - but... fast tanks with a great aesthetic. Sold.
Which brings us to the real treat that is the Blood Angels codex. Not only does it meet my weird expectations, but it exceeds them. Its a wonderful army book. Tons of cool toys that are also solid choices, plenty of ways to build in order to be effective and lots of character. I like the models, I like the color red and the rules are great. Its a win/win/win situation.
I understand that there are people out there who are more qualified to review the Blood Angel units Than I am. So I won't pretend I'm an analytical genius with an expert tactical acumen. That's not what people come here for. I'm pretty sure its the bad jokes, swearing and painting. In that order. However, I still want to talk about the rules and the units and why I like them.
Which brings us back to jokes and cuss words.
I'm just gonna shoot out some kind of general reactions here. I had gotten a fer peice down the road to a unit by unit analysis before I realized that it would be even less fun to read than it was to write it. So I'm just going to take a look at general trends that have gotten me pumped about the new codex rather than waste everyone's time with a piss poor review. That's what BoLS is for. Zing!
The Good:Descent of Angels: This is pretty sweet. Its a very cool ability that really opens up some possibilities for some new kinds of builds and makes the Vanguard Veterans a usable unit. Which is pretty important if/when I decide to jump pack it up. Double bonus points for that since the Vanguard models are so great.
Jump Packs Everywhere: Not really a rule, but very cool. There are just a ton of units that have or can have jump packs. Combined with Descent of Angles, you can really rock some very fun sounding and cool looking assault armies. Especially with the Sanguinary guard. Chumby's got a list up that looks like a ton of fun. Just wish I could tell if he's serious. Unfortunately, as cool as DoA and jump packs are, they're edged out in my mind by...
Fast Vehicles: Awesome! Almost everything is fast. 18 inch max movement and can still fire everything up to 6 inches. When I got confirmation that this was true, I immediately smoked a cigarette. Then I pooped. For me, this is where it's at. I love tanks. Fast tanks in particular. Though not as fast as my Eldar , the Blood Angels get that crucial ability to move up to 12 inches and still shoot. They also have more than one build and have fewer useless units than the Eldar. A pretty good trade for 6 inches of movement.
Land Raiders as Dedicated Transports: This fun fact is only just 'interesting' by itself. Land Raiders are cool and all, but they're huge point sinks. Combine the transport option with a jump pack discount and things just got a little bit crazy, though.** Heavy support or dedicated transport, it all shakes out about the same in terms of how many you can cram in 2000 points: you can't have as many as you want. Though the flexibility of being able to take them outside of heavy support is quite nice.
Assault Squads as Troops: The big thing here is that these guys are just so sick. Over regular Smurf assault marines, you get the ability to take two kinds of melta weapons, way more transport options and Descent of Angels. All for the same cost. The biggest draw for me is the transport discount. I know a lot of people don't much care for anything resembling Razorback spam for the Blood Angels, but where else are you gonna get this deep a discount on so many fast tanks? Beyond that, the assault squads have so many options that they really open up the codex to so many opportunities for list building that it's mind blowing. Which is great for the painting and modeling side of things. I'm hard pressed to think of any other unit that can be this flexible in terms of list building.
Super Dreadnought Fun: Have you ever looked at the regular marine codex and thought: "man, six dreadnoughts just isn't enough"? Well what about being able to take 11? If your like me, you have a boner for robots right now. Attention everyone: do me a solid and don't harsh my buzz with 'facts' and 'logic' about not being able to fit 11 in 2000 points, or not being able to capture objectives or any of that type of crap. I need this right now. Just let me pretend for a little while longer.
Predator Spam: You can take six of them. SIX, goddamnit! And they're all fast. That's so much dakka it should be criminal! In the spirit of full disclosure, the existence of the Baal Predator is the real reasons I've decided to go with the Blood Angels. Forget jump packs, feel no pain and librarian dreadnoughts - its Predator tanks first and last. No matter what happens, the first army I build and paint will have all 6 possible Predators.
Feel No Pain Ever Again: Its all over the place in this codex. Which is great for jump pack armies and pissing people off in general. I, for whatever reason, am not that excited. Don't get me wrong, its a pretty powerful build option and very cool, but the Sanguinary priest models are dull and I'm not all that attracted to the type of army that would best make use of this ability.
Special Characters: Not really impressed with these guys as a whole. Though, Dante, at least, screws around with the FOC in a meaningful way so he gets a bye. There all just so 'over costed with nothing to show for it but a bunch of gimmicky bullshit. Plus, most of the models are ass. Which is what kills Mephiston for me (who is otherwise awesome). I hate hsi model and at 250 points, he becomes a centerpiece. Not really interested in the Duke of Slappywag being a centerpiece.
Stormravens: If this had a model at launch, I'd be more pumped. As it is now , it's just a cool idea. It doesn't really exist for me. I'm sure that when the model comes out in 6 months, Ill consider getting three. But at this point in time, I have no desire to fiddle around with expensive conversions that will be blown out of the water by the actual kit.
Red Thirst: I actually, really like the idea of this rule - it adds character to the book and is a fun random chance kinda thing. But... that's about it. It's a real 'meh' kinda deal. Not something you can plan on taking advantage of. From a fluff perspective, I like it. Otherwise, I don't care.
A Brief RantI've looked at this codex a lot. I've read all the good analysis about it I could find. I've even played against it. While it's certainly excellent, It's not overpowered. I bring this up solely to bash the guy at the LGS who was bitching about how he didn't like the codex because its too good. Course he's an Ork player so that might have something to do with it. Now, this was a conversation held cordially between strangers, so it wasn't all RAWR!
First, he was mad because of the Storm Ravens. Then I pointed out that you can only have three and that he should be worried that all the fast vehicles (which are annoying, granted). Then he was mad that marines were faster than his Orks. Which was "a problem". Then he started bitching about the Matt Ward as the author of the Fantasy Daemon book. Apparently Matt Ward made the Chaos Daemons too good in fantasy and, thusly, all his works deserve hate.
Most importantly: HE HAD NOT EVEN PLAYED WITH OR AGAINST THE BOOK!
Bah! I left the store with my purchase knowing that I had met one of those stereotypical complainers that plague the likes of Warseer.
So that brings me to the end of my feelings on the new codex. Not particularly logical in a lot of ways or even with a complete attention to competitiveness but that's how I do things.
*cough Dark Angels cough
**Well aware of the 'controversy' over taking Land Raiders as transports for assault marines and so forth, but c'mon: this is all the proof I need.