Here's a direct test to show you exactly which one is the best theme.
Both these WordPress Themes have the same Elementor Page Builder Plugin installed and Both Use the exact same Elementor Page Template.
To test these themes yourself, Use Google Chrome / Inspect Elements / Network. Or use any other tools you know of to determine the best theme for yourself.
My test results between Customify Theme and OceanWP Theme:
WordPress Customify Theme has 44 requests and a page size of 1.5MB
WordPress OceanWP Theme has 50 requests and a page size of 1.6MB
No other performance optimisation tweaks were used. I did disable scroll to top function on OceanWP Theme and adjusted some padding from within Customizer to get as a close as possible look on both themes.
Email me at: admin[at]pi.x10host.com (trolls will be ignored or published on the global troll list)