When choosing your hardware, the SBC community is not relevant since you will be deploying a NEMS server specifically. For example, the ODROID C2 vs Raspberry Pi 3 comparison will say Raspberry Pi 3 has better support for video drivers. Well, that shouldn't matter to you; you're using NEMS and we've pre-built the distro for you. So because of this, we've compiled this list to help you select your hardware based on NEMS, not general usage.
Capabilities: (theoretical - will have to test for real numbers) Up to 100 hosts and 1000 services.
Pros: Lowest cost solution, runs cool,
Cons: Significantly slower, Only 1 GB RAM and no possibility to upgrade, slow SD card reader, Ethernet is 10/100 USB 2.0 is shared with the network port so networking will slow down if using heavy load on external storage.
Coming Q4 2017
Capabilities: (theoretical - will have to test for real numbers) 500 hosts, 2500 services
Pros: Significantly better performance: 8 cores up to 2.0 GHz, Gigabit Ethernet, 2 GB RAM (twice that of the Pi 3), SD card slot is significantly faster (UHS-I)
Cons: Runs hotter than Pi 3
Coming Q1 2018
Capabilities: (theoretical - will have to test for real numbers) 10,000,000 hosts :D
Pros: Low power consumption and footprint for a powerful unit, 16 GB RAM, M.2 storage, Gigabit Ethernet, Runs cool with passive cooling technology (no fans).
Coming Q3 2018
Pros: Utilize existing virtual infrastructure
Cons: It doesn't exist yet