I have to agree with the original poster, although for different reasons. There is a lag, but that is something that can be tweaked and fixed. My problem is that the multiplayer game is largely unplayable due to fatal errors that occur. These have been reported to Matrix/Slitherine (check out the tech forums and you will see). If you only want to play one battle against an opponent, you might be able to get it to work, but if you want to invest the time in playing campaigns (as I do) then you may be in for disappointment. I really do believe that the multiplayer mode was not well tested because we found problems (my friend and I) within the first 30 minutes of playing the game and now the game has no value at all for me until they patch the program. It's a pity because it looks like a lot of hard work went into it, and I hope that the fix is fairly simple but so far, no patch is forthcoming. So, like the OP, I feel that as an early adopter (I bought the game the morning it was available) that I am giving Matrix/Slitherine money that they really haven't fully earned yet.
The bugs that are coming up are not things that are frustrating but can be dealt with while waiting for a patch (like tanks taking a strange path) - these are game stoppers in that they cause the program to completely crash (a variety of internal errors, etc). There is nothing the user can do in this instance, and the game is rendered unusable.
In short, if you want multiplayer, don't buy this game.... yet. Wait until they fix the problems. I hate having to pay to be a beta tester, but I guess this is a lesson for me to learn.