These tiny speakers (only 7" high and 2.5" wide) do, indeed, provide an inpressive volume for their size.
They appear to be robustly built and solid.
The main reason for 4* and not 5* is that the sound is a bit tinny. They're fine if you want to use them as straightforward PC speakers, but don't expect a warm, rich sound for listening to music. For that, I think you may need to pay a bit more than these.
Having said all that, they are cheap, solid and perfectly servicable. I would certainly buy them again as replacement for the old, failed speakers on my desktop PC.