1. create NFS shares to present to ESX for virtual machines

Use the DSS and create a NAS Logical Volume then create a Share and enable the NFS file protocol. Store your ISO images for VMware.

2. create snapshots, backups and then sync to a standy DSS for DR?

Using another DSS use the Auto Failover feature ( see link below for more details).
Currently I have not had time to test all the other features with Snapshots and VMware.
For the Backup you can use our NAS Backup feature via a mapped Share from the NAS Logical Volume.

Library
Product Presentations

http://www.open-e.com/library/product-presentations/

2008 - Open-E Volume Replication with Failover over a LAN, December