I've now played this game a load of times - tutorials,single player against the AI, and online.
Brilliant game - Very different to all the other RTS games I've played, very clever, and very enjoyable.
Also very difficult, which is no bad thing - nobody wants to win easily, and there are nuances to the game that are becoming more apparent. Little tricks that make a big difference, and coping strategies, like shutting down your claims when someone messes with your power, before you send up in a 30K hole!!
I have had quite a few frustrating games where I felt like I was doing ok, and then just lost in 30 seconds without understanding why. In a more conventional RTS game you usually see the enemy coming, and whilst you may be helpless to stop them, you can see what they're doing, and try to learn from it - Getting pounded with helicopters? You need air defences!!! Etc. In many of the games I have lost, I could tell the other player had a lot more cash than me, but couldn't understand what they did better. The end of game graphs etc may reveal some of that, but either they could tell me more, or help me understand what they are saying more. Losing a game is fine if you can learn and try to improve - losing and having no idea why can be incredibly frustrating, especially if you felt like you were doing well!

One main thing has been bugging me though, and that is offworld trading.
After a while I realised that it is literally the be-all and end-all - No matter what strategy I tried, nothing became remotely successful until I laser focused in on that one part of the game. So now when I play, it's literally all about upgrading as fast as possible, trying to build the offworld trading building (or two), and trying to stop the opponents doing the same. And that seems a shame, because it seems to prevent effective use of some of the other mechanics.
I realise there will always be an end game, and that all players will work towards the most powerful weapon available, but it feels like it would be better if there was more than one route to success - an equal to the offworld trading building, so that people could win in more than one way.
Now that's just my opinion of course, and most people may disagree. It's also possible that I'm just plain not good enough at the game yet to be able to use more strategies - I don't pretend to be an expert.
Just thought I'd feed back - The game is brilliant so far already, and from my perspective, a few extra tweaks and it could be truly epic.
Thanks.