Welcome to the "LED and Other Lighting" part of the forum.
Since this is about HID, you will receive more info elsewhere.
However, I've looked into these for myself, and have read reviews of plenty of people that use them. They work, but like many things, you get what you pay for.
They create a lot of heat, and it's not easily removed from the growroom. Since it's a self-contained unit, they're heavy. They almost always use a magnetic ballast(old tech). They're not very efficient at producing light (lumens per watt), despite advertising that they do.
You want something new and relatively inexpensive, get a Ceramic Metal Halide. You can run them in the open air, with a remote ballast, and they run cooler than an HPS or traditional MH. They run off cheap magnetic ballasts, so your investment is pretty small.
If you want to get into LED's instead, stick around and read up.