Well, KoR | Layouts used to be one of my favorite servers (besides AA). Sometimes the human base would start in the bunker on these layouts. Then you got to see the true use of the bunker location. The aliens often staged-up faster, as outside isn't as human-friendly as the halls. The alien base was sometimes not built up, but usually that depended on how well the humans did.
If the humans got S2, and managed to secure jetcamp, the bunker base was pretty good, but if the aliens managed to keep the humans from getting an air force, or attacked later when the air force is disbanded for chainsuits, the base proved to be *VERY* snipe-able, and only one or two humans can attack goons at the entrance at once. I can't imagine it would be good with mara-zap either. However, the humans do have the advantage if they can control outside due to the alien base being so close.
The main thing is that if you can prevent jetpacks from getting outside in S2, which can happen even if the humans reach S2, via dretch poison, tyrant camp, a few acid tubes (not too many though, as meisseli pointed out), then the humans are toast.
Its mainly a bad move due to it being very snipable, and dies a lot before it is fully created. However if you can hold the area just outside the front of the bunker, you do gain the advantage.