Nephilim Jetfighter
The Nephilim Jetfighter is the Dark Angels' air superiority fighter. It is flown by the Ravenwing to allow their ground-bound battle-brothers to focus on catching Fallen Angels SHOWING THEIR DEVOTION TO THE EMPEROR without having to worry about getting attacked from the air.
The Jetfighter was added to the Dark Angels' Codex in 6th edition to help set them apart from the other Chapters of Space Marines that get their own codices. The lore justification is that the Dark Angels had the Jetfighters for longer, but only recently found the STC pattern of a superior engine that made them practical to use (though given that the Nephilim is neither Supersonic nor Fast, the previous engine must have been really bad to force the Dark Angels to keep them grounded).
Nephilim Jetfighters pack a twin-linked set of heavy bolters and six "blacksword" missiles (36" S7 AP3, named because of their black smoke trail -- which is a lot more sensible than the Blood Angels' "bloodstrike" missiles), with a choice of twin-linked lascannons or an Avenger mega bolter in the nose. Not the most difficult of choices.
This fighter is excellent proof that if the different organizations of the Imperium would learn to share and not be selfish assholes, the Long War would be Long Over by now. Seriously, the Dark Angels use this thing to mow down every enemy air craft, even Eldar (the ones who get 40-1 kill-death ratios against Lightnings). Do they share this with the Guard? Hell no! They don't even share it with other Space Marines. The jerkasses could at least give the Guard and the Navy the data for making damn blacksword missiles. Screw the Mechanicus, they have enough toys to dickslap. Besides, if they got it no one would hear of it again for a few centuries, if ever.
Dark Talon
A variant of the Nephilim, in the same way a Darkshroud is a variant of the Land Speeder (both are rocking the "Bolt a bunch of kickass masonry to the hulls" look).
It's got a Rift Cannon (a STRENGTH 10 AP 2 BLAST), two Hurricane Bolters and a Stasis Bomb. It lost the Hover Strike special rule but it gets Strafing Run base.
All complaints about this thing are gone. It doesn't need to "Hover" any more, so it can drop a can of derp on a unit, then use the Rift Cannon to obliterate anything (it becomes a Vortex is you roll doubles for scatter) and it can shoot 12 BS5 re-rollable bolter shots to take out hordes. It's weapons may not exactly go hand in hand, it can come on, take out/debuff a unit for your Knights to take care of, then Rift Cannon the heck out of some termis or a vehicle. If your opponent has a couple large squads, the hurricane bolters will take care of them.
It may not have any anti-air capabilities, but the Dark Talon got a huge buff in 7th.
Tabletop Analysis
The Nephilim and Dark Talon are rather unpopular choices for a Dark Angels army, but their weaknesses have kinda been blown out of proportion. They're not bad, they're just overpriced and overcosted for what they can bring. 7th edition gave them more buffs, so they certainly aren't bad, more in the realm of iffy.
Both flyers suffered the sin of being the second "true" flyers out of the gate in the 6th Edition: The Heldrake that preceded it was rapetastically awesome (until the 7th ed FAQ) showing that the design team were still trying to figure out how these newfangled rules work. It was only after "Death from the Skies" came out that pre-existing Storm-talons/ravens became proper flyers as opposed to fast skimmers and they already had enough firepower to get by in the 6th edition environment, they only really needed (and received) the "flyer" rule to be added to them.
Anyway, onto the Dark Angels. For 170 pts you get a TL Heavy Bolter, six S7 AP3 missiles with Missile Lock, and an Avenger Mega Bolter. The only problem so far is this isn't the "real" AMB, it's a stripped-down AP4 version. For 5 points you can swap it for a TL Lascannon.
The Nephilim is great against skimmers and other light tanks, but an 175 point investment that can't kill AV14 and takes three or four turns to kill AV12 is just too iffy for most players. That's only 25 points less than a Stormraven with the same lascannon + heavy bolter loadout. But the raven has far better missiles, +1 AV all round, ceramite plating, power of the machine spirit also has a transport capacity and can carry dreadnoughts
Alternate take: God damn does this thing sucks. A twin-linked heavy-bolter with either a twin-linked las cannon, a buffed assault cannon, and four regular assault cannon strength missile shots. For 180 pts. Its incapable of any serious anti-armor role with only one las cannon, and four, limited use, assault cannon shots. Anti-infantry is a better role for it but between the Black Knights and Deathwing Knights they already have that covered. And with no other anti-air most DA players will be looking at it for turkey hunting, its weaker build, instead. The heavy bolter is also something of a crutch, with no way to replace it for something more useful at all. Its okay in the infantry build, but utterly useless if you intend to do anti-armor.
Dark Talon
As for the Dark Talon, it's far harder to directly compare to any other flyer since nothing else performs a similar role. Dropping your opponent's Initiative and Weapon Skill by 3 is always hilarious, doubly so when you drop a Blind test on his snipers immediately afterwards, but for 160 points the fact it has only one bomb and the lack of AP wasn't doing it any favors. But that was 6th ed; this is 7th ed where it drops a S10 AP2 Blast that has a 1 in 6 chance of becoming a Destroyer Vortex. Fucking hell YES!