Compression, checksumming, unlimited snapshots, etc, etc. Too many features to list. I want ZFS because I know ZFS & ZFS doesn't lock me into storage. The initial price point of EMC & NetApp is not too bad in some cases, agreed. It's the support contracts that get you. Like I said before twice, no thanks. Not interested in 3PAR or Dell Compellent or anything else like that either.
Performance goals? Something ideal for running about 20 VMs. Fully plan on taking advantage of SSD cache ZIL/L2ARC.
Capacity? 20TB raw should do it
Plan right now is to share storage out to a Proxmox Cluster via NFS. Not touching iSCSI.
The original post was simply "Anyone had any experience using iXsystems TrueNAS, specifically in a clustered configuration?". That's still the question.