Keep in mind that there is such a thing as too much power on night dives. You run the risk of chasing off the fish that you are there to see. I think that the 2500 spot/flood will do you well, and I also think that you will find, at least in clearer water, that you will prefer the medium setting once your eyes adjust to the darkness, especially if looking at sea life vs structures.I think it's safe to say that whichever way I go, I'll question if I should have gotten the other light
If I get the combo light, I'll probably wish I had more power in the beam. If I get the Pro, I'll probably wonder how good the flood mode would look under certain situations. I'm leaning towards the Pro right now because as a beam it would have great power, probably would have a lot less particulate scattering, and hopefully I'm less likely to piss off or blind a dive buddy.
Erik