I'm probably close to being the average Bitcoin user:
- with very average technical understanding
- owning a modest sum of coins (and in possession of and controlling even less)
- using mainstream consumer hardware and OS
- transacting at most once a day

I've tried many wallets in my time and Electrum is still the best fit for me, based on above reasons. As others point out, that the developer(s) behind Electrum respond quickly and effectively to vulnerabilities makes me even more confident. That said, I don't think I can ever trust anything I don't fully understand. That's not a criticism of Electrum, that's probably just a best practice of security.