Both are very easy to use, but I will say that if you want to spend as little time as possible building your site, Strikingly is the better option. However, Strikingly has relatively few templates on offer, and you can’t change the look of your site in a meaningful way because customization is very limited.
Wix gives you far more creative freedom, and has over 500 templates to choose from – even on the free plan. It takes a bit longer to get used to, but if you’re serious about your website, it’s worth spending the extra time.