Ok to be fair here it always has to be taken into account what is at risk. Don't store a lot of funds in an online wallet, but you also secure mytherwallet quite well. If you need a wallet for regular transactions it is not that bad.
Aside from that.
Be also watchful to the gas fee of ethereum with the use of those websites that monitors it like ethgasstation.
I can only give a positive report about mytherwallt when it comes to gas fees and the adjustment is very easy. But the price range of the fee is in accordance with what is show on the respective websites like gasstation.