If Jaxx is not save, then does that mean all the mobile wallets are insecure? Then where should i keep all my coins?
In the history of Bitcoin I found that we have problems only with the third party wallet and that will results into lake of trust of save your money safely in the online .
So here I will recommend to use only blockchain.info wallet because blockchain.info is available at every type of platform , I means to say that we can use it at web desktop as well as at the mobile platform easily and also in blockchain wallet we have the option to pay the customised fee .
So why we should use another third party wallet , So use official always have no fear in our mind because official are always best and they will responsible for our any type of loss .
Yes you're right about using wallet having a third party, like coinbase it uses third party so its not so secure.
Try electrum its a desktop wallet and acts as a cold storage wallet but you can installed it in your smart phone or tablet.
It's great for back up and for storing huge amount of btc. It's an offline so it will not get hack.
For your everyday transaction just use coins.ph , it's safe to use and doesn't use third party.