I'm a real estate investor myself and other than property values, job market in the area, demand for rental units and the politics of a city is what i look at before I buy anything in that city to hold for long term. With that said, I think Long Beach is the best coastal city in LA county to invest in right now. Here is why:
1- The property values are still relatively affordable allowing for a better cashflow potential.
2- The city by itself has major industries that support the community and jobs. The port, the CSULB and Long Beach community college, the memorial health care facility and the air port are a few examples. There are always demand for rental units.
3- We have 710, 405, 605, 22 and 110 freeways easily accessible to us. We also have easy access to public transportation. These all make it very easy to commute to anywhere in Los Angeles or Orange Counties for business/work.
4- Long Beach has everything in itself. We have museums, play houses, night life, all kinds of food and shops, hotels, hospital, parks, convention center. We host major annual events like the Long Beach Grand Prix. These all make it a wonderful place to live in.
Hope this helps. If I could be of an assistance please feel free to call me. I'll be happy to answer all your questions with no strings attached. My contact information is below.