San Diego and Orange County are more similar than most of the other comparisons on this page, both coastal Southern California counties with a suburban, family-friendly reputation.
What's actually different
Orange County sits closer to Los Angeles job centers, which matters if work ties you north. San Diego's downtown core is more built out than any single OC city center.
Housing comparison
Costs run comparable overall, with the specific neighborhood mattering more than the county-level comparison.
What San Diego transplants ask about most
Commute to LA-based work, and which OC beach cities most resemble San Diego's coastal neighborhoods.