When it comes to someone saying, "this is how much I bench" and then they show you some half ROM press.... That's lame. If someone is in the gym not being a braggart, forcing hypertrophy into different parts of his muscle by exercising various ROM, I think that's good money - creative.
So many variables to account for when benching also... Prior injury, nursing a current injury, sticking point training with competitive lifters, muscle symmetry training for bodybuilders, isolation...
But if someone claims they bench more than you and do some pump rep that doesn't lock out or doesn't hit their chest... that's equivalent to doing a quarter squat.
I've gone to only paused reps on the chest for the last 11 weeks and my form thanks me. Just saying...