Cost. The drive is about $40 from our Amazon store. The unit we purchased for evaluation was from Best Buy.
Advantages. An external hard drive docking station makes it possible to purchase inexpensive internal drives (when they go on sale) and have access to them outside of your computer for a fraction of the cost that a complete external drive would cost. External drives can be easily plugged in when needed. Separate drives can contain files from different projects or different years of archived data.