I've checked the wiki, these forums, and the main site, but I can't get a clear idea of what the current release of the full version has beyond the demo.

1. How many more missions are there?
2. How many more buyable items?
3. In what ways is skirmish expanded beyond removing the 6 min time limit?

I really like this demo and think I might want to pay the $18, but I'm not exactly sure what I'll get.

uuhhh... well you get the map editor.

you have a point.

but when B23 comes along...

Basically, if you buy it now, you never buy it again.....even when there are future versions.

This is the most notable concrete benefit, I think. That, and you get the various editors. When the game becomes more developed, more features may be locked. What is certain, you will be buying Cortex before the price hike which seems to be close now, what with the engine mostly finished.

To sum this all up (even though Duh pretty much has),

You get Cortex Command for $18 and not have to pay again even though the final price of the game will be about $40
There is no time limit
Should you ever become a modder, there are some editors that are very useful at times

There will likely be more things that will be disabled in the future demos. So, for instance, once the campaign is expanded, it will probably not be available aside from the tutorial and maybe one other mission.

You still have to buy CC Expansions when they come out.
But yeah, buy now, save some money, or buy the Special edition.

CC Expansions? I never read any mention of CC expansions... please explain this to me.

Hmm well I'm really tempted, but if all the full version gets me right now is some extra modding ability then I'll wait. I was hoping it would have more missions, more items, and especially improved AI (I get pretty discouraged seeing a rocket slam into the ground because it never had any thrusters, or watching my units destroy each other by walking by).

Going past the six minute limit is really quite good, not to mention you'll be getting those improvements later, but cheaper than if you wait.

why yes, there will be more of everything in the next version. Also,

well, there are speculations that CC will have expansions, BUT that will be really far away from now...

Basically just mods you have to pay for.

Ok, basically, if you ever plan to play to game in the future, buy it now

Think I'll wait until there's more skirmish missions and more campaign mode.

Yes, and wait until its more expensive. Time is money.

The point that everyone is trying to make and that you seem to be failing to get is that if you wait then you will have to pay full price for the game.

The point of buying it now is so that you NEVER have to buy it again. 20 dollars is much better than 40. Unless you have a money tree in your yard or plan on buying the support version it is best to buy it now.

Plus if you download the map packs in the scene section there are a lot more skirmish maps. Tons. I don't think that I've even used all the ones I have yet.

There are also a few nifty missions there too.