Those are commonly known as "Esbit" stoves, for the fuel they burn.
I've used them, but I don't really love them. The fuel is relatively compact and it lights easily, but it's expensive in terms of cost per meal worth of cooking. Also, they're really only good for boiling water for wet meals or beverages, since there's no heat control and the burn time isn't long enough for a long session anyhow.
If you want a super compact and lightweight stove and you're at all handy, google "penny stove" and see my preferred method for an alcohol burning stove made from a couple of beer cans. I made one quickly a few years back when I started ultralight backpacking, thinking I would make another one "right" when the first one stopped working. Problem is, it still works great!
For vehicle-based camping, you're probably going to be much happier with a more conventional stove with a burner control, etc. I'm heavily invested in white-gas (coleman) fuel appliances, so I stick with that, but most here on ExPo like propane, etc. Choose the fuel that works for you and then pick your price range. Everyone will tell you to spend the $$ for a Partner stove, but many people have a hard time getting a cheap coleman stove to fail, so choose your battles.
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