I bought a "not working - for parts" Netatmo on eBay a few years back. The remote sensor was indeed faulty.
I took the sensor module apart and found suspect looking solder connections around the main IC, which I assume is a processor. I resoldered all of the terminals, and it has worked fine ever since.
About a year ago, I purchased a NovaLynx 380-601 Small Instrument Shelter. I relocated the Netatmo into this shelter and I get readings that agree with my multiple Davis temp sensors within a couple tenths of a degree. From this, assuming you get a good one and it is properly shielded from solar heating, it is not all that bad.
I think that the mistake is that you can mount the rather dark silver sensor by itself, which is asking for trouble.
I recently received the rain gauge as a gift. It also seems to be working well.
Originally, I had a bad impression about Netatmo, but more recent experience has been better. Of course buying a $325 shelter for it would be ridiculous. (I bought it to house an old-school Taylor Orchard min thermometer, and there was plenty of room for the sensor)
Greg H.