The biggest risk in my eyes is getting your phone stolen. Since that's always a possibility, I would protect whatever wallet you use with a solid password that won't allow access to your coins unless it's entered correctly. Some wallets use PINs, and I'm not sure how secure those are.
Electrum wallet is not the best for a mobile device and you should not assume that your coins is safe just because you use it.
It's definitely got a decent reputation, and I think you could do a lot worse than Electrum for a mobile wallet. I've used it with no problems in the past, as well as Mycelium. There are so many available, and I haven't used most of them but the password security issue goes for any of them--and always back up your wallet with the seed phrase or whatever a given wallet gives you the option to do to back it up.
If you are looking for enhanced security, you should not use a hot wallet, but rather cold storage in hardware wallets or well Air gap devices.
Well, I totally agree with that but OP asked specifically about mobile wallets, so I think he's looking to use one.