I haven't used bitwala, how can you say that bitwala isn't safe if they are providing their users to have their very own private keys? In what aspect of their service they are lack of security? I used few wallets like, blockchain.info and xapo but I left xapo since it has high fees now. If you want to be safer you had to spend some and invest with hardware wallets like nano ledger s and trezor. But for cheaper but intact security, desktop wallets are good.