Blood Angels: An Outside Opinion
If it wasn't clear by the title, I don't play Blood Angels. I don't want to pretend that I do, or even have in recent history (though I did play them when Furioso's were new models and weighed 3 pounds). That said, this book has some really interesting stuff that's making it's way though my little brain. Instead of breaking down the book, unit by unit, I'm going to use a more holistic approach, and talk about how I about the book as a single entity. I will also point out what units I think work well for the play style I think it encourages, and maybe some that don't, but don't expect it to get that deep into the exact wargear that I think a unit of Death Company should be carrying.
A Drop (pod) of Blood (Angels)
Right out the gate, the Blood Angels book appears to be one built around a devastating drop pod assault. Their tactical squads get access to an inexpensive heavy flamer, meaning they have the only heavy weapon that's effective the turn they land. Every slot, save heavy support (unless playing with FW, then Deathstorm Drop Pods), has a unit or two that are particularly effective when given a drop pod. Out of HQ you can take Librarian Dreadnoughts in pods, Elites can be filled with Command Squads laden with meltaguns, various dreadnoughts, and the classic Sternguard. Troops like I said would be tactical squads, you can take 5 with 2 hand flamers on the sergeant for a devastating flame attack, or take larger squads with another flamer, or combat squad them for 2 meltas (combi on the sergeant), and a 5-man with the heavy flamer, there are plenty of options here. Out of fast attack you have probably the most under priced option, Assault Marines in drop pods. For a mere 105 points you can take 5 Assault Marines with 2 meltaguns in a drop pod, and for 30 more you can give the sergeant 2 inferno pistols, giving you an effective 4 meltaguns in 1 drop pod for practically nothing. If you want to make matters more interesting, in Leviathan Exterminatus, there is a detachment allowing up to 6 fast attack, so for 1215 points, you could end up with a mixture of 9 5-man squads in pods, either 5-man assault marines with quad meltas, or 5-man tac squads with heavy flamers and 2 hand flamers. That's pretty damn gross.
What of Jump?
I know that before, BA players were quite proud of their troop based Assault Marines... I know this because of all the crying and moaning that has surrounded the rumors of the release. As if to predict this, Games Workshop has already released a Detachment that allows players to take 6 fast attack. Unfortunately however, I personally think that jump troops still aren't that great in the game, regardless if you can take a large amount of them or not.
In addition to the new 6 fast attack Detachment in Leviathan Exterminatus, there is another one that gives you a totally different army, one comprising entirely of up to 16 elites choices. I'm not sure if it'll actually be that competitive, since it's only restricted to "veteran" units (____ terminators and ____ vets), plus only Furioso Dreadnoughts (not other kinds for some reason), but it does give the whole detachment the old Decent of Angels 1D6" scatter on deep strike. One formation in particular that I think is opening up a world of possibility is the Angel's Fury Spearhead Force. It has a long name, but holy hell, is it worth remembering. It contains 3 Stormravens, and 3 10-man tactical squads that are deployed inside them. The formation lets the Stormravens roll for reserves on turn 1, with a re-roll, and it gives the tactical squads objective secured. That right there would be good enough for me, but to make it better, if anything deepstrikes within 12" of two of the tactical squads (which it seems works if they're in the storm ravens), it can assault the turn it deep strikes. So when you take this detachment and combine it with either the pure elites detachment, you can do something like having 2 Furioso's drop in turn 1 and charge on the tail of the 3 flying on Stormravens.
As Imperial Knight Allies
Naturally, I need to think about my own bias. The Angel's Fury Spearhead Force is pretty fun to think about, but really, you can only fit in 2 knights along side it, which would leave you with a Tactical Marine as warlord. That said, I think it would be a pretty fun, and maybe even effective army, but I think there are better options. The Blood Angels book brings a very devastating drop pod force, which fill the need for anti-transport and objective secured very well, though they're incredibly light on AA, basically relying on Storm Ravens, which are good, but very expensive. Some hyperios platforms can help shore up this weakness, but they're nowhere as good as they once were.
The hordes of veteran BA players are braying about how their codex got nerfed for XY and Z, exclaiming that their hordes of previously used assault marines will continue to gather dust. Being a total outsider to the army, I see the new codex as a devastating Space Marine list that is thoughtfully designed to close the gap and get right in the face of the enemy with upmost efficiency. Like everything else in 40k, things change, new strategies evolve, and if you want to be competitive, you're going to have to adapt.