Two types of lists have evolved out of the new codex – razorspam and the beautiful DoA.
Razorspam basically consists of five to six predators (maybe a Vindi) and the rest of the army is small five man assaults squads carrying meltaguns riding in razorbacks. There will be a Librarian or two with Shield of Sanguinius and possibly even a Sanguinary Priest. The predators screen the razorbacks for cover saves and the Librarian casts Shield for extra protection. All vehicles in the army can move 12 inches and still shoot. The army has no assault element whatsoever and can generate a moderate level of shooting.
DoA stands for Descent of Angels. This army consists entirely of jump infantry and possibly Stormravens transporting dreadnaughts. Everything starts in reserve. The jump infantry units are typically bristling with meltaguns and infernus pistols… these units can reroll a failed reserve roll and only scatter d6 inches. This army is one of the strongest in assault, has excellent short range firepower and is highly mobile. These armies tend to be small and don’t have any long range firepower unless Stormravens are fielded for much needed heavy support.
In my opinion DoA is much stronger than razorspam, however razorspam is more popular because it is an EZ Win Button army. That said DoA is still popular and could become more so with the coming release of the Stormraven model from Games Workshop. I have played my DoA army versus BA razorspam… have not lost a game against them yet.