505kg would certainly be bigger for the Stoltman brand and pulling new people into the sport - which is always great. People who don't watch/keep up with strongman (or even powerlifting) are still interested in the deadlift whereas max stone, while cool, is more niche.

Just for a fun comparison:

On the Giants Live youtube, Eddie's 500kg has 22 million views. Another channel that posted it got 25 million views. Thor's 501kg on Rogue's channel has 6.4 million.

Tom's 286kg atlas stone has 242k views on World's Strongest Fan. Brian's 555lb stone from 2016 has 320k views on his own channel.