I will choose polkadot then BSC, because of the developer if BSC is gavin wood. And the uses case for DeFi is more in polkadot then BSC. It will take time to create fulky functional system but dot will made it in the end.
That could be the main reason why there are lots of people have been betting on POLKA. gavin wood is the reason why polka was doing good.
We know that gaving is also in the same team with vitalik butterin when ethereum was created in the past.
Binance is offering useful product but polka has a bigger ecosystem compared with binance. We are seeing so many new platforms joined in polkadot ecosystem.
That could be a big bet to be the best alternative chain for ethereum.