I am using GlobalSAN with my DroboPro, since the DD beyond 1.8.4 is terrible, and the latest version (v.126.96.36.1999) supposedly corrected the sleep issues. And I was able to sleep the Drobo.
I don’t run in 64-bit mode but if you want to do so, I’ve heard the ATTO iscsi initiator is very good. It is a more professional iSCSI software and supports 32 and 64bit on Mac. People said it’s faster and stabler than the free GlobalSAN initiator. The catch is that it is $195, and some people on this forum bought and loved it. http://www.attotech.com/products/product.php?scat=17&sku=INIT-MAC0-001
For me, I’m still thinking if it is necessary for me to spend that much money on a piece of software that only work currently with a DroboPro since I don’t have other iSCSI devices yet.
If you do buy it, let me know how well it runs because I really want my devices to work well and run stable all the time…