I actually bought one recently from China and it arrived damaged (mounts broken) so I haven't tried it out yet. I've got my money back and am deciding what to do next. These machines are quite compact and appear well enough made. The cooling is done via a pump (supplied) so set up on a board is advisable to avoid mess. The instructions are a total joke-even for Chinese gear. Having inspected mine-they are all pretty similar-there is no way I'd recommend it for club use. The makers claim that it pumps up a cylinder up to 500cc in quite a short time to 300BAR but don't look to be able to fill your dive tank with one of these. It just isn't part of its spec.
I used a home compressor made in Korea for several years and found it very useful but when it gave up the ghost I couldn't find anyone to service it.