As long as Tyranids and Necrons actually are released I am fine with either. Some very vocal and very minor minorities are crying for releases of dark eldar and Adeptus Mechanics fleets...neither were very much blessed with Model variety in the Tabletop.
I am glad we can choose SM Chapters (Dark Angels hooray) I was fearing the Canon-friendly (regarding the Gothic Conflict) Angels of Redemption or the standard Ultraboringmarines only.
Also the release sported VARIANTS of the Eldar Ships. This should help swat the annoying "no variety" cries a lot...and it gives me hope for also a more varied SM Fleet.