[SLCNPezz]

sigh its not safe to expand at all if you're doing a phoenix mirror. You have exactly the same tech paths and unit count, where is your advantage coming from? The only advantage you have is phoenix rally time, that's not enough to justify 4 additional zealots within your opponent's army. If you want to try phoenix mirror against me that's fine, I will show you why you can't expand unless behind a forge. The timing will hit as your nexus finishes and you will be down 400 minerals worth of units, lose the fight and ultimately the game. Or else you can sit on your ramp and lose 400 minerals as he kills your nexus for free and takes his own expansion.

edit:

I've had so much discussion time with NA grandmaster phoenix users on this subject, it's not even debatable, nobody in high level play will take an expansion in a Stargate mirror unless you have either A) Gained some ground in the early game, or, B) Gotten a forge and cannons up before his push hits.