They're all pretty worthless. Checkr couldn't verify almost ANYTHING about my background. HireRight called my CURRENT employer for a job I had 8 years ago, said "unable to verify dates", then when I pointed out the obvious problem (they verified the exact dates of my current employment down to actual start date), they just closed the whole process with 'unable to verify'. Of course, none of it mattered, because the employers don't expect them to do a good job anyway, so they hire you regardless. But god forbid you actually have something in your background that needs research/explaining.