Lived in North County precisely Sabre Springs and Rancho Penasquitos for 2 years after living in Tustin Ranch for 10years. I found San Diego to be very expensive( I know that sounds ridiculous, because people think OC is very expensive).Everything to me was expensive, utilities(this include water, waste, gas and electricity), groceries and life in general.Utility is provided by the county and with that monopoly, the prices are outrageous(Gas for me was $200, water $250, electricity $400 , I did not live in a mansion). Maybe, if I lived in Chula Vista I will be singing a different song, even my colleagues who lived in Chula Vista complained about the crazy utility bills. In both communities that I lived in , we only had an Albertsons, Vons and Stater Bros in Rancho Penasquitos(these were miles apart) and no grocery store in Sabre Springs. If you wanted anything ethnic you had to hop on the freeway to Mira Mesa(7miles away)or El Cajon(18-20miles away). In OC, regardless of whatever city you live in you have choices on where to find food and utilities are not that crazy.
Traffic is horrible due to the topography of SD.There are barely any side streets that are more than a 2-3 miles that you can take to avoid freeway traffic. Unlike in OC, where streets run over 10miles straight and cut across different cities.