Rent
Neck and neck
Irvine and St Louis are about even on rent.
Irvine
$2,150/mo
St Louis
$2,150/mo
What this means for your life
Typical rent in Irvine is $2,150 a month versus $2,150 in St Louis, close enough that housing cost should not decide the move by itself. Factor it into your budget alongside salary differences between the two markets, then pick the city that wins the categories you actually live in: safety, schools, pay, or weather.