Personally noise isn't an issue even though I have 5 hard drives in my workstation. Heat however is very important and can kill a hard drive over time. External enclosures are horrible for daily uses as they slow and allow drives to get hot. Plus they are problems in the making when concerning most users who at least once drops the enclosure while a drive is installed. Worse while the drive is powered up and in use. In the end its better to keep them inside the machine or outside as a bare drive.