I paly them as a second army. Although my models are low and I don't have a lot of options for building an 8th list.
It looks like the new codex wants to be more static than previous armies. And Deathwing get bonuses to teleport and shoot. Ravenwing is speedy and durable.
I suspect most armies will have a bunch for small squads of Greenwing with one or two large units of Deathwing or Ravenwing.
The Chapter Tactics aren't terrible, but they aren't amazing. The rule itself is solid, but neither will come in to play that often. Ravenwing and Deathwing want to move. Deathwing is fearless. Greenwing will probably use it the most, but MSU still seems solid and with ATSKNF they aren't likely to lose a lot of models anyway.