Both has pros and cons. None of them are good in my opinion because web wallet are risky because of getting hacked and mobile wallet is also the same. But if you consider the features may have, I would go with mobile wallet.
Web wallets are even more dangerous because they can get compromised at any time, mobile wallet is safer than web wallet unless you fall for any kind of phishing scheme or you reveal your private key somehow, web wallet don't have private keys or recovery seed