I do, on a MacBook Pro though, not a PC.
I've experimented a bit and find a 7200rpm USB3 3.5" drive works OK, but I've not tried streaming more than 24 tracks at a time in that setup. A 5,400rpm bus-powered drive can also do reasonably well, again so long as it is USB3. Putting an SSD on a USB connection doesn't make much performance difference to an HDD other than you can't send TRIM commands over USB at all, so the drive may tend to slow down somewhat as it gets used.
It helps if you partition the external drive into e.g. two partitions then use the first partition for audio spooling. That's the partition which will be physically nearest the outside edge of the platters and therefore, because it has the same rotational speed as the inner partition but a greater circumference, have a higher read/write rate.
Unless you have a high track count you might find a USB3 external drive works pretty well but the only way to know is to try one and see.
An SSD connected via Thunderbolt 2 is as fast as an internal SDD, and Thunderbolt does support TRIM.