Be careful about depending on an agent to find you a place. They usually show you everything other than what you are seeking and most expats Ive met who have used them were not happy with them. They are only interested in getting a commission from the landlord/owner so don't think they have your interests as priority.
Ive lived in Tijuana, Rosarito & now in the Ensenada area and I would definitely recommend Ensenada as it is farther away from the border so you have less "undesirable" people due to the distance. There are more deportees in TJ & Rosarito than the Ensenada area and the expats here seem to be more higher-income than in the other two areas. You might check the La Jolla/Punta Banda area as it is nicer than e city of Ensenada and much less noise and mostly Americans. You have to remember the closer to the border you are the more you have to deal with crime and illegal activity.