BEP20 is cheaper. either sending from a crypto wallet such as trust wallet or from an exchange. If I'm not mistaken TRC20 requires a fee of 1 USDT while BEP20 is only around 0.2 USDT 
I have made USDT withdrawals several times and the fees on each exchange are not much different.
Yes, Bep-20 or BSC platform tokens can be transferred from one wallet to another wallet very easily and with very low fees. For which its popularity and usage has increased the most. People now mostly use the BSC or Bep-20 platform to send USDT because the fees here are much lower than other platforms.I have made USDT withdrawals several times and the fees on each exchange are not much different.
But now TRC-20 platform charges higher USB withdrawal fee than BSC platform.Because today when I withdraw a few dollars amount of TRC-20 USD from one of my wallets, 13.66 TRC fee has been deducted which is worth 1.52 dollars according to today's market. But if I want to withdraw the same amount of dollars from my trustwall to another exchange or wallet, it is only $0.08 which is very less compared to TRC-20 platform. So I don't choose BSC platform i.e. Bep-20 to withdraw any stable coin because the fee is very low here.