It's been a while since anybody commented on this, but i feel there's a room for a little more analysis.
I have concluded by experience that keeping or losing the middle is pretty much the main deciding factor in the game. Other than that, it comes down to cost efficiency, hard counters (T2 air and stealth) and finally unit composition synergy (T3 massive balls).
The above in general leads to the following rule that should be kept to win the game:
1. Build enough units to keep the middle
2. If your army consistently wins, you can take a minor setback and add a geyser
3. Only upgrade tech if in dire need for a hard counter (you are being hard countered by stealth/air), money spent on tech is pretty much wasted unless those units are what is needed to push the enemy back
Taking a geyser is basically gambling for more long term resources, sacrificing your short term income. If you do this while politely letting your enemy take the middle (i mean not building enough units), it leads to a snowball effect where your significantly smaller army will be hard pressed to make a dent in the enemy forces. This is why pure eco based build orders don't work.
Eco + Tech is right out of the question, and will lose you the game 90% unless your teammates make up for your very weak (or in some cases nonexistant) army.
Fast tech might be viable, but the surprise factor needs to be enough to make up for the lost resources and weaker economy, also preferably the teammates need to keep the pressure on. The more you tech the more risk you take and the more weight you place on your teammates. OFC this is why multiple people fast teching usually results in a very fast loss.
Cost of Eco:
I disregard the middle here. The best time to take your gas is when you are not YET controlling the middle, but your army is capable, and is fighting/winning it. You should lose as little middle time as possible to the gas delay. Also, avoid taking the gas at the same time as your allies, at least SOMEONE should benefit from the middle income, if you have it.
1st Gas: 100 + 125 (takes 250 seconds to make up for it's price)
2nd Gas: 100 + 275 (takes 500 seconds to make up for it's price)
3rd Gas: 100 + 468.75 (takes 568.75 seconds to make up for it's price)
4th Gas: 100 + 725 (takes 660 seconds to make up for it's price)
5th Gas: 100 + 1062.5 (775 seconds to make up for it's price)
(6th Gas: 100 + 1500 - not in game as of now - would take 914.29 seconds to make up for it's price)
So, as you see, the first gas puts you behind roughly 2-3 T1 units in army count (that is why usually everyone takes it right at the start), the second puts you behind 3-5 T1 unit worth of minerals, or 1-2 stronger T2 unit.
My recommended order and usual strategy:
- If i'm first, i take no gas, build units until my spawn timer expires, and then take 1 gas. If i'm not first, i build a gas, and as much units as i can crank out while i spawn.
- Keep the middle as much as possible, only tech to T2 if in need for an anti-hard counter (remember, T2 is a net loss of 250 minerals without any long term benefits)
- Take a second gas, then, if you are comfortable with your army power, tech to T2
- Take third gas
- Delay T3 as much as possible until needed (sieging the fortress or needing the splash damage or tanking power)
- Fourth or fifth gas is very beneficial if you think the game will last long, and you feel you are able to keep the enemy at bay.
Subject: Income 2.0 
Mon Jun 06, 2011 9:32 am
