Not really, that works if you want to have converged storage in your hypervisors, but most large VMWare deployments I've seen use external storage from remote arrays.
Shared across a cluster of multiple hosts, such that you can hot migrate VMs? I am not aware of that being possible in Proxmox the same way you can in VMware with VMFS.
It's not like VMFS (not a cluster filesystem), for Proxmox+iSCSI you get a large LVM PV that gets sliced up into volumes for your VMs. All of your Proxmox nodes are connected to that same LVM PV and you can live migrate your VMs around all you wish, have HA policies so if a node dies its VMs start up right away on a surviving node, etc.
You lose snapshots (but can have your SAN doing snaps, of course) and a few other small things I can't recall right now, but overall it works great. Have had zero troubles.
