No noise - you need only pay attention to sufficient convection in the housing should be made of aluminum at best. For it is no ATX power supply no longer fan available. Knowledge you also have that a maximum of two drives can be connected. For the second SATA drive you need an adapter from Molex to SATA. But for the particular application (office computer with an SSD) the little thing is just awesome.
If it is reported here that the power consumption has dropped by 40% compared to an ATX power supply, is likely to be due to bad or defective ATX power supplies. I can not confirm that (so). For a NAS or a server I would not use that thing. Since I prefer a ATX power supply, because such devices should be anyway actively ventilated.