I got mine at my local headshop, but you can get them at a lot of hydroponic stores or order online. Mine is a HydroFarm model, 6bulb 4ft.
Temps are the real reason i went with it, as its hard as hell to keep things cool in my house. I keep my plants small and bushy, and my yield (as i dont have any other experience to compare it to) doesn't seem to have suffered any, but there's no way to truly know that for sure. One thing i CAN say is that all 3 of my bagseed plants came out Dense, Sticky, and stinky, though the one thing i dont have to worry about in my house is the smell.
Only issue i truly ran across is light penetration, but i think i found a way using lst to circumvent this. Passed that, i couldn't be happier =D