I have tried a couple of Proxmox clusters, one with overkill specs and one with little Mini PCs. Proxmox does eat up a fair amount of memory, but I have used it with Ceph for live migrations. Its really useful to me to be able to power off a machine, work on it, then bring it back up, and have no interruptions in my services. That said, my Mini PCs always seemed to be hurting for RAM. So that's my pros and cons.