Generally speaking, hard drive cases do not offer more protection than another case. If you drop a hard drive while in its case, the resulting shock may displace some of the hard disk platters which will ultimately prevent the disk from being read. Additionally, a fully enclosed hard drive case is not healthy for the hard drive if the case does not provide a way for the hard drive to radiate heat. Please note that hard drives are one of the hottest (temperature wise) devices running in your computer. The friction caused by a spinning hard drive is what generates the heat in a hard drive so you must ensure that the hard drive has proper cooling available to it.