– Reliability: raspberry PI work on linux system, arduino version use programmed microcontroller. I suppose that a monotask program is more reliable that a full OS. Am i in wrong? Is it possibile to prevent critical issue like flooding for unclosed pump?
I think this really boils down to software design. There are tons of modern gadgets built on embedded Linux and they are very reliable. I did receive some reports about SD card corruption issue on the Pi, which is rare but exists. So at the moment the arduino-based version is probably more reliable, but I think the pi-based version can be improved to have similar reliability.
– Heat dissipation: this point depend on the first one. Raspberry pi works at higher temperature and the enclosure doesn’t help it. Somebody have tested it in critical environments?
I haven’t done any critical testing under high temperature myself. RPi generally dissipates more heat because of its current consumption. This could be a problem during the summer particularly if the controller is placed outside under the sun.