I tested the GB-4510. It's nowhere as clear as the Hawkeye pictures that you see online. So I was a little disappointed. Then I ordered the Lyman Borecam to see how they compare. The GB-4510 is significantly sharper than the Lyman. I really don't like the Lyman. The resolution is too low for me to detect carbon rings, etc...
I'm sending it back the Lyman and keeping the GB-4510. It's no Hawkeye , but it gets the job done for half the price.