Bitcoin Core is the most secure wallet, if you need better feature you can try Armory.
And usually hackers hack wallet from virus / malware
Many people can't/don't use them as Blockchain needs to be downloaded and it is over ~30 GB. So SPV clients like Multibit or Electrum or hardware wallets or paper wallets are their choice.
-MZ
yes, whereas with current connection speeds of DSL/cable/cellular access downloading 30GB shouldn't be such a big effort and can be run as a background task.
Even if it takes a week to do, it is worth the effort.
You can still sign the spend the funds even if the blockchain isn't downloaded. Wallets like electrum would be much easier since they have a gui. The difference between bitcoin core and other wallets are very small. Bitcoin core just offer the advanced features a technical user needs. Whereas other wallets offer typical user one would use to secure their coins or receive/send bitcoins.
Download and upload speed isn't as important as the possible bottleneck in your CPU. Slow CPU takes loads and loads of time to verify all the blocks. Also, if there are no Bitcoin nodes which is near you, the speed would be reduced greatly.
