It's actually quite good. There is a fair bit of fluff, some cool artwork, 2 formations and all the requisite rules from C:SM. In short, all you want from a Dataslate. I definitely think this isthe way forward for expanding the universe, it's much better value for money than the supplements and can be produced much faster.
The TWVs themselves are basically sternguard squads of 4-10. They area bit cheaper but only have hellfire bolters and zealot (this is only against Tyrannids). This is fine in my opinion. What is cool however is the St Tylus battle force which allows you to have up to 6(!) Stormtalon gunships with a modified version of infiltrate - they start the game deployed in hover mode. This has scope to be a barrel of fun, especially if you go first, imagine all the carnage you can reap with at least one full turn with all your flyers in the board from the get-go!
In conclusion, I'm happy with the Dataslate. I'd much rather have these micro rules sets in WD but I doubt that will happen, so this is a good direction to go in. If your mates play Nids then this is worth a look, if they don't...well you can't go wrong with deployable flyers.