We are currently using it in production. Initially it had a major issue with rebooting, as the iscsi stack would cause the system to hang for a LONG time when booting. However, VMWare has issued a patch that resolved that problem. So long as you apply the patch it seems to work just fine. Though how it handles MPIO is somewhat different than before.
Oh, and we DID have trouble with a version of Open-E that was 3 versions old not working with the iSCSI. This was easily resolved by updating to the latest version though.