Well aside from the longevity and efficiency....LEDs have yet to penetrate and build buds like HPS does....

Forget about an A/C....I mean A/C is good to have but if you want to run CO2, in a sealed room, water cooled lighting is the way to go.... Get a chiller with the equipment that goes with....and temps will be a breeze to handle....

Since you say that money isn't a prob....get both LEDs and HPS HIDs.... After a couple grows....let us know which lamps you'll be putting up for sale.... Personally....I'd go with the proven and tried method of lighting....not the still in development period method....But that's just me....

CGI::::::