How does the HDhomerun compare to built in TV tuner?

How's the HDhomerun compared to the built in TV tuner? Do you get any extra channels or is it pretty much the same as the built in tv tuner when using the same antenna? Ive got pretty good coverage, but would love to get some of the Canadian signals that show as bad but I would think that would need to be antenna first. I know its unlikely but a guy can dream about Canadian news

https://www.rabbitears.info/searchmap.php?request=result&study_id=2322272