I've got three Adaptec external enclosures and its one of the few I'd consider expecially for bigger drives...their enclosures support HDDs up to 100GBs.
Four weeks ago, I purchased an ADAPTEC 3.5'' hard disk enclosure case for a new 120GB, Western-Digital, Caviar, hard disk, that I had kept sealed in the original container for several months. Initially, the hard disk enclosure worked beautifully with my Windows Xp notebook. Then several days later, the hard disk could only be read intermittently. After two more weeks of frustration the hard disk failed.
Presently, the hard disk has been returned ''under warranty'' to W-D in California. They have indicated that they have received the disk. And all appearances are that they will replace this failed hard disk. However, do keep the ESD packaging for your new hard disks, because they want it returned in that bag. It cost $8.00 to UPS it back to W-D and they ''strongly encourage'' you to use UPS.
I don't understand how a brand-new hard disk could have failed so quickly? I never dropped it or submitted it to any kind of physical or electrical shock.
While it was 'dying' I did have many times when my PC would not recognize or read this USB 2.0 external hard disk. But, I don't believe this is the fault of the USB 2.0 ADAPTEC hard disk enclosure case. However, I guess I won't know that empirically until I have a new hard disk in this enclosure and have used it for awhile.
Previously, I was using USB 2.0 San Disk flash drives to back things up. But, then the unthinkable happened....the flash drive failed! Now, I backup to two flash drives and my external hard disk. My hope is that the external hard disk will prove to be sufficiently safe and reliable storage.
Hope this helps someone,