In my opinion, BNB has a rapid development compared to ETH, slowly BNB will grab the ERC20 network and become an independent coin so that it will be stronger in the market position, the Binance team is currently preparing a network that makes it easy for BNB users to do anything.
Though I'm not a fan of ETH.
But when it comes to ETH and BNB I still would go for ETH.
Due to the fact that I see BNB as a coins that is centralized. We all heard what happened when Binance froze the account of a scammer who stole huge amount of BNB.
It's a common thing I guess since Binance froze the account in the Binance exchange so that scammer won't have time to move that huge amount of BNB to another address. Imagine that scammer sold a huge amount of BNB, it will make another dump to the BNB market.