portable external drives for playback and light editing?

[timepresent]

What are folks using for Macbook Pro playback and light editing (e.g. 1/4 resolution in Premiere) when you can't carry around a raid array? (As in the field or while traveling)

Has anyone tried the Samsung Portable SSD T1 1 TB External SSD? ($480) It is USB3, which is the downside, but still seems to achieve real world transfer of 400 MB/s+ which is on par or faster than many SSDs on thunderbolt (non-raided).

Wondering how that will hold up with 4k

Thanks!