it really depends on the game and map.
all games i've played so far as vasari on the beta i've never ever build any phase gates because starbases can do that now and don't take up any tactical slots.
by the time i got returning armada my fleet is usually huge and i have enough ressources to build up the 2300 supply.
for the time beeing i must say phase gates are useless now.
i have not tested the latest changes in beta 2.5 yet, we'll see.