I also tried it at Umami Burger, but mine was cooked medium. It dripped pinkish juice similar to a medium-cooked burger. I found it surprisingly close to the real thing. Most people would guess correctly in a blind test, but if you served it to an unsuspecting person, they'd probably think it was the real deal.

One caveat: I may not be the best judge of accuracy. I eat meat maybe once every three months (usually by accident or because my alternative is to go hungry).