I have the same motherboard and its been running great for three years. Just recently switched out the dual e5-2670 v1's for 2690's v1's for a small boost in performance as well as get rid of the 8x8gb (64gb) for 8x16gb (128GB). I'm running ESXi on it but I've been recently thinking about switching to Proxmox since the upgrade.
Proxmox is super easy, I have not run ESXi in a long time so I cant really give a comparison.
The AsrockRack EP2C602-4L/D16 is a really great board, I have had mine for a little over three years and has been %100 reliable the while time except for Windows 10.
Only issue I had was trying to run Windows 10 bare metal on it, not the only one that had issues with Win 10 on this board, but it ran Win 8.1, Windows 2016 Datacenter server eval and win 7 with zero issues.
Been running Proxmox since then.
Just added another 32 Gigs of ram about five minutes ago, its ram I had laying around unused and been meaning to add for a month or so.
Still running the 2643 V1's and I have been overprovisioning the vm's with more cores and more ram and so far have not reached the limit of it. But I rarely run more than eight or nine vm's at a time.