The physical one, which is more reliable to boot because it's emulating the actual USB-DVD/USB-HD/USB-flash interfaces when you use it.

https://www.iodd.shop/IODD-ST400-USB-30-External-Encrypted-H...

I love using my IODD in "dual-mode" with Clonezilla. It exposes a USB-DVD drive with an emulated Clonezilla DVD in it as well as its' HDD storage so I can dump an image right to the hard drive.

(Bonus points: I can then have Clonezilla bundle me a clonezilla-iso package of my captured image, and save it back into the ISO folder to boot from later!)