Metamask is easier to manage multiple accounts transaction in simple clicks.
If you are with Ethereum only transaction, coinbase can be easy.
There is private key associated with every wallet address, you can easily manually use them to operate multiple accounts from myetherwallet.
You are right, I agree. Metamask very easier to use. My experience has a 150 ether address in one account (metamask).
I've tried to use imToken (Android wallet), but maximum can only accommodate 10 address.