I own a 250 watt MH/HPS called the Pulsar Mini made by Sunleaves it came with both a 250 MH and 250 HPS bulb both were made by GE the ballast is INSIDE the unit and with a flick of a switch you can use either bulb(one at a time) I paid $130.00 for it and have been using it now for 2 months been growing with CFL's for 2 years before this.
I am using it in a closet enclosure I made and only have a little more then a 2x2 space so its perfect for me I am using 1 - 3' foot tall fan and the area stays around 76f room has a AC of coarse, I also have 2 150watt cfl's on the side's just for a little extra help.
Normally I grow short AutoFlowering plants but a friend gave me a clone of some kind of Cheese and it is loving the light.
Each bulb(MH/HPS) puts out just over 20k(20,000+) lumens, while this light is weak for most if you dont have the room you can't beat the price for what it can do and what it contains(Light Kit-Ballast-Bulbs).
There is a 400watt version of it also but after using the 250 for a while now I am glad I didnt go with the 450 as that would have been too hot for a small space.