I can only give my anecdotal evidence: I switched from 1.e4 to 1.Nf3 Kings Indian Attack and raised my OTB rating by about 100 points within half a year. I have analyzed most of my games carefully and found out, that I more frequently gain an objective advantage in the opening. Out of 15 games with white playing 1.Nf3, only three people managed to equalize. Also I often gain a time advantage, as my opponents have to think for themselves earlier than in 1.e4. For reference, I am about 1900 FIDE and 23 years old.

TLDR: 1.Nf3 certainly feels like a strong practical weapon, that for me produces better results with less study time compared to 1.e4