I would say SS has vastly outperformed reasonable expectations based on pre-release reviews, and has even somewhat outperformed expectations based on pre-review hype. I would have said $500 million would be a decent result for a movie with few true headline characters, and the Joker while well known among movie goers is not your traditional idea of a headline character to attract a big audience.
OTOH with BvS those are the two most recognised and beloved superhero characters in movies (possibly alongside Iron Man now, but that has only been recent). And that movie underperformed given that the 2 immediately previous Christian Bale outings are both the $1 billion club. The one thing BvS has going for it is that it's the highest grossing Superman movie of all time, significantly outgrossing MoS and Superman Returns.
Taking into account the $75 million lower production budget for SS, I would say everyone in the biz would call SS a better success than BvS.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
