Submersable vs External which way you go??

[banditpowdercoat]

OK, I am wondering the pro's/cons on Submersable and external pumps. I know External needs a bulkhead fitting on sump, but why would one choose one over another? Do submersables have shorter lifespan? I am thinking a Mag 18 for my Sump, but then, I could go a little more fro flow. And it isnt that much more to jump to external for as far as the pump costs.

Just wondering why you went with the pump you did??