For years, I've been maintaining benchmarks for microSD cards on the Raspberry Pi, but I only spent a little time testing external USB storage, due to historic limitations with the Pi's USB 2.0 bus.
But the Pi 4 cleared away the limitations with a full-speed USB 3.0 bus offering much better performance, so I've done a lot of testing with USB boot, and with all the USB SSDs I had at my disposal. You can see some of those results in this blog post and video on booting a Pi 4 via USB.
After posting my tests concerning UASP support in USB SATA adapters, I got an email from Rob Logan mentioning the performance of some other types of drives he had with him. And he even offered to ship a few drives to me for comparisons!
There's also a video that accompanies this blog post, for the more visually-inclined: