Segate 4 tb expansion is the worst external hard drive in market because it can not be taken outside due to unavailibility extra power connection it needed for running the hard drive with the laptop. Also if you want to connect it with your phone it may not support to your phone whether it has a android or ios platform, forget about windows. Some times luckyley it it compatable with smart phones.
So with respect to harddrives which can be operated without exra 220V power supply it is worst in performance. 4Tb is just the only factor which may drive you to buy this product obviously in lesser price. But remember it will not be portable unless you find a power souce.