HDS initially said it was a bug but version after version, they couldn't resolve the issue. For me, it really means HNAS is not designed for VMware workload which is highly random IO with low latency. Don't believe their PR, 2M IOPS means nothing if latency is 100ms.
Management is another thing, with SAN + NAS gateway model, you will have to manage 2 different components. NetApp is truly unified, and you can use VSC to provision or OnCommand/command/powershell to create/export volumes and mount on esx.
BTW. back in 2 years when we deployed HNAS, there was 128 file system limit. Not sure where they stand today.