Choice will depends on many things if compare them. If its about long term profit, then I'll choice bnb. cause after pos update of eth, there's no difference between two. Eth fee also reduced a lot but bnb still charging cheaper. But the main reason for choosing bnb is, bnb still have many facilities to unlock and developed like eth already has. While bnb will take those steps and make complete, bnb grow speed will be more faster
If it's for the comparison of ETH and BNB about the projects that they've made through smart contracts then, it's incomparable and ETH is dominating in that area.
Although both really are good to have and ETH is burning fees while BNB has a burning too IIRC, every quarter so, investors are loving that feature that both of them have in terms of burning supply to make it a deflationary cryptocurrencies.