C-class neighborhoods there are ideal for Section 8 and long-term renters.

I personally would avoid the older neighborhoods closer to the post.

Quote from @Andrew Steffens: If you search on Airbnb in that area you are not finding any PMs at all? 

i offered on one i really, really wanted last month in a neighborhood i own a rental in. 

Here are a few suggestions on how you can maximize the wealth of information available: Check out the blogs and podcasts, or take advantage of the search feature (magnifying glass).

My client is interested in investing in a new-construction build of a 23-unit apt. complex in a great neighborhood in San Diego. 

I also searched both these topics with no luck.

This will help you in the long run, as you'll find your agent experience will be a blessing & a curse:- Blessing due to your understanding of MLS, searches & contracts.- Curse because MUST change your agent mindset.

Some of my clients love the cash flow in the east side neighborhoods over by Slavic Village and Broadway selling between 90-110k with rents up to $1,800+, but just really depends on the types of neighborhoods you're investing in and your risk / reward threshold. 

You can sidestep most of the headaches if you stick to these five golden rules:- Know Your Market Inside OutTake time to research neighborhoods, property values, and what buyers are looking for.