hi there
basically its a confined grit type blasting unit, very similar to closed cabinet blasting machines where an item is inserted into the cabinet and then blast cleaned, the grit is then recylcled and reused.
the benefit of the system is that it reuses the blast media, an therefore contains the cost.
i do however doubt the lack of PPE on the users, blasting equipment is very dangerous if there is any failure therefore i would want to be properly protected.
as for the speed, i does appear slow, therefore large areas may prove slow going.
re health and safety, mention media blasting to any local authority or any client really, even if it is a contained system, and they will want every piece of paperwork that you can imagine.
regards
martin