It's ideal for small jobs or small parts. You can reuse the media, if you can find it. I use this outdoors, so I usually don't/can't. I bought this specifically to clean up rust under my 80s and to use for restoring a couple of antique tool boxes, which will not fit in a cabinet. The Armex/gun removes paint and leaves a paint ready surface finish, but will not remove rust, which I use fine sand for. On a medium size toolbox (24x12x16) I went through about 25 lbs of Armex and 5 lbs of sand. That's prepping inside and out, but just the box, not the drawers.
The hopper will totally empty in 5-10 minutes; this thing really uses CFM, just like a cabinet. It really strains my little compressor. There is no flow control; it's either on or it's not. One word of caution, though. This thing was not only made in China, it was designed there. Apparently in China, a valve operator, such as the one below the hopper, crosses the valve when it's open and is inline with the valve when it's closed. I have been using this for a while and it's still baffling/not at all intuitive.
It does work, though and you can't beat it for the money. There is only one moving part, the valve operator, so there's really nothing to fail. Even if there was, it's $20.