Okay, so the game's out in less than a month and I'm only just playing the demo, but never mind!
The demo gives you the tutorial and two battles. I didn't do well on either (but then I didn't expect to - I never do well because I've never played enough to get the hang of resource management) but the Tau look good.
Everything you'd recognise looks right, although the voices weren't quite what I was expecting. The main buildings look suitably Tau-ish, and it is great to see the build animations as you create your base. Some of the more advanced buildings are quite unique with some fitting design as well.
From more of a modding point of view, I also like the new 'exclusivity' of upgrades/buildings. Build one building to follow one path and it locks out the other, which stops you building the units that require it. Not too much impact in the demo as most of the second building's units can't be built in it anyway, but certainly useful for people planning to mod Chaos to be god-specific
Now, considering I've never finished the DoW campaign and haven't started the WA one (I've only ever really modded) do I need to pre-order DC?