most if not all of electrum is open source,and i never had any problems with it,in that past hack we learn that we should only be careful with any "update" messages coming from strange links,that's how people got hacked and lost all their balance in the past,other than that its a almost perfect wallet for me.
Electrum is a good choice, but make sure to get the legit one; when searching for it on Google or mistyping it, you can have some malware-infested
.exe's pop up, disguised as 'Electrum'.