the second one can be found for a little cheaper at bgh i believe.
Ballast creates little/no heat.i strongly disagree..i have grown with both and there is a big differance..i have used 150's for well over 10 years and have set many of buddies up with 150w hps setups.
my buddy went with a all in 1 ballast,bulb,reflector 250w and in the same room a 250w remote ballast setup and there was a 8-15+ degree differance between the two boxes. if its hot you can always vent for better temps but i always go for the cooler way right off the bat.
I suppose if noise is an issue I could always place an aquarium nearby and the sound of the pumps and filters would hopefully drown out the buzzing from the grow.