I have lived in the Newport Beach area which is right next to Irvine for over 20 years. Irvine is a very nice area, and I believe annually amongst the lowest crime rates in the country. The schools are good, and there is an absolute ton of new product coming on the market. Prices are higher by a fair amount than comparable properties in San Diego. Traffic is not nearly as bad as SD. Prices have begun to come down, but very slowly. I think your rent will be more money than what it would be in SD county by a few hundred for the same thing.
I personally like SD county better than OC which is why I am buying a house down there right now, but you cannot go wrong in Irvine.