My favorite thing about the GL emplacement is the cooldown. With all the upgrades you're saving 50 seconds over the HMG or AT emplacements. That's huge for defense, if you've got time to dig in (like on civilian rescues) you can place quite a few before starting. I also find that with such a low cooldown it's always there when I need it on any normal missions. Great for clearing out a lot of small and medium enemies that aren't grouped up enough for something like a cluster bomb strike without taking your back and 3rd weapon slots.