I think BSC remains the best because BSC can achieve a block processing time of 3 seconds by using something called Proof of Staked Authority (PoSA), where participants stake BNB to become validators. Importantly, there is no subsidy for newly minted BNB as BNB is not inflationary and its supply decreases over time as Binance regularly "coins burn"
While Polygon currently only supports Ethereum bases, the network intends to expand support for additional bases, based on community suggestions and consensus. This will make Polygon an interoperable decentralized Layer 2 blockchain platform.