I'm always trusting ETh. The reason is BNB just a new coin that related to Binance exchange. Last few months i saw the BNB price around 600$ suddenly. The Reason that i highlighted the project management of the exchange. They are doing it nicely by bonding BNB. But for the With there is no unique exchange and it boned with block chain.
This is where ETH is different from BNB. ETH is not owned by a centralized exchange, whereas, BNB, it is owned by top centralized exchange. What will happen to BNB if something goes wrong with Binance? Though the likelihood of falling down is very minimal, still the chance is still there. But if you are holding your BNB on their platform, it is pretty secure as they have insurance. Both are good alts to invest with. But up to you how you will allot your funds to them.