Both are good, but you can look at it from different points of view, such as speed, security and cost.
Ethereum has a problem with gas fees, but ethereum is safer because it uses POW consensus, then BSC comes with lower transaction fees and makes a lot of changes because of lower transaction fees, but what you need to see is, before BSC was created, Ethereum had seen problems that and they will activate the Beacon chain, both networks are good and you can use both as you wish.