Info about working external drives with new iMac

[davidra]

I have heard from Micronet, the makers of my Fantom GreenDrive, that their drives need a firmware upgrade to work with the USB 3.0 bus on the iMac (which explains why my drive disconnects when the computer goes to sleep). A thread on the Apple support page notes that some WD drives have the same problem (in fact the Fantom drives could be WD drives; I'm not sure). Clearly manufacturers are having problems getting their devices to work solidly with Apple's USB implementation. What I would like to know is what drives are people using with a USB 3.0 interface that are working perfectly with their new iMacs? In other words, they don't disconnect frequently, especially when the computer sleeps.