With external SSDs, the main advantage over hard drives (HDDs) is clearly speed. Furthermore, SSDs are also usually available in smaller form factors, which is more convenient for transportation. Unlike the HDD, an SSD has no moving parts and is therefore more shock-resistant.
When buying an external SSD, pay attention to the storage capacity. Rather buy a bit more storage than too little. If data transfer speed is an issue for you, you'll be happy with an SSD that supports higher read and write speeds. And last but not least, the interface is of course also relevant for the purchase.
It is also important to make sure that the storage medium is compatible with your operating system. Most external SSDs today are compatible with Windows, Mac and Linux.
You can find external SSDs from Samsung, Sandisk, WD, Angelbird, G-Technology, Freecom, Kingston, LaCie, Seagate, Toshiba, Transcend and Verbatim.