But I can trust it for 200+ W readings? That's what's really important for me right now.
Yes, IMHO you can, with some error margin of course. If for example your PSU has power factor of 96%, then 200W corresponds to 208VAR (I mean device will show 208) - not so big difference. With PF=99% there's only 2W (or VAR? Let's say 2 units
) difference, this is similar to error margin (good devices have accuracy about 1-2%, which corresponds to 2-4W error).
And you can compare loads with less (absolute) error too.
Good enough for now then. The reason I like the expensive WattsUp is the USB connection in the Pro Version. That would allow me to make more serious analysis of the power consumption. (To be honest, good digital multimeters will also provide an RS232 port for the same purpose, costing less and being more versatile, albeit more complex to use.)
Interesting, are such devices for "normal" EU sockets available? (Haven't seen here in Estonia.) Needs to search on .de or .fi domain
Yep, that's the issue for me too (and no, I havent' found them with the EU socket). Sure you can put an adapter in the back and another one in the front, but that makes the thing bulky and inconvenient. Another interesting feature of the WattsUp in this department is the international Universal Outlet (IEC320) version. It will work everywhere. They even provide you with the right cables for each region. Considering the current weakness of the US dollar, buying from Europe is not that bad. Oh well, let's sell a few workstations first...
If you want to search in German domains, the thing is called "energiemessgerÃ¤t" or "energiekostenmonitor"