I ordered two boards with N355 CPU: one for NAS server and second for Proxmox server. I installed 48GB RAM in both motherboards.
First boot takes a bit longer because it seems it detects the RAM. If you change the RAM memory it will take a while the first time it boots, the rest of the times it will be as fast as expected. Plenty of choices to tweak in the BIOS menu. The fan (Noctua NH-L9i in my case) will not spin when CPU temperature is low which is great.
NAS server: great choice because its 6 SATA ports + 2 M.2 ports + PCIe x4. I use a RAID PCIe card to allocate all my storage devices. It works great. Motherboard + CPU power consumption about 20w idle with a few storage devices.
Proxmox server: great choice again. I used 2 nvme storage devices to setup a mirror to increase data security. I can run many containers and virtual machines with 48GB of RAM. You need more RAM than CPU for Proxmox so maximizing RAM is a good thing for this setup.
I have just two recommendations: (1) add the audio pins to connect to the tower. I know it is completely useless for typical use case of this motherboard, but it is a nice to have feature. (2) My second wish is for the inner USB ports: just use the board pins for the USB ports and if someone wants to use them to attach something, let them buy the cable, as if not, the usage of these two ports is quite limited because they are not easy to use once the tower is prepared. I plan to buy a remote KVM board to control these machines from remote (even reinstall the OS).
Really happy upgrade from my previous AMD Ryzen 3600 that was using way more power than these two servers at the same time.