GW is releasing the BaC sets as individual boxed sets. There will be a MKIV Power armour set with 10 marines: options for flamer, meltagun, plasma gun, heavy bolter, missile launcher and Sgt. as well as a single guy with a combi bolter.
Cataphractii terminators: 5 figures with options for twin linked bolters, powerfists and a heavy flamer or lightning claws.
Contemptor dreadnought with either assault cannon or multimelta.
Space marine heroes with a Praetor and a Chaplain.
Looks like each boxed set will be about 30-40 quid.
If you are starting a Legion the BaC set will definitely the way to go with 3 of the PA guys and 1 each of the rest but if you just want a dreadnought or some MKIV guys to mix in with your other marines this would be definitely an option.
Or you can't save up $150 USD at one time.
Hopefully this means that they plan on expanding the range with some other sets in the future.
I'm good on marines for my World Eaters at this point. I do need a couple more rhinos and some drop pods but probably won't buy any of these sets for them.
I might buy some of the PA marines to try some paint schemes for the Ravenguard, Death guard, thousand sons or Emperor's Children though.