I'm in Orange County, CA. The only city/area in O.C. that I've actually used 3G is in the City of Anaheim, and it is really bad. Other than this area, I'm always on wi-fi.
I live in Orange County too, and Sprint is really really bad here. As mentioned above, videos take forever to load and apps take a long time to download. Loading images is really slow too. Wish I didn't have Sprint but oh well.