Voidstar is a waste of time unless you're on the attacking team first. Defenders start with 3-4 people meaning they cannot cover the doors. This leads to quick plants of bombs. By the time defenders become attackers, the teams fill and those defending have no chance to plant as quickly. This coupled with the fact that Voidstars are longer rounds, it's often better to simply leave, take the 15 minute hit, do heroics until you can queue again rather than waste time in an assured loss.