Even in bulk, the reward vs number of people needed is far away from other methods.
I got the same bunker IIRC, the Zancudo closest to the sea. Much better entrance than the cheapest one or the most expensive, there's plenty of room to land.
As far as the vehicles, I got nothing so far, most of the things that I wanted are being drip fed. I'll probably get all the cars, the Bombushka, then maybe I'll think about other planes. I'm planning on changing everything that I have to the coast and that's going to cost a lot (bunker, office, vehicle warehouse), so the money for any vehicle is going there instead.
I liked that they let you try most of the planes / helicopters during supply / sale missions. Nothing so far made me go "wow", not even the Hunter. Hydra and Buzzard are still kings of PvE.