Remember though, each entity (LLC, partnership C/S-corp) will cost you a minimum of $800 each per year in California. If these were multimillion dollar apartments that may be a good idea (I'd have a good lawyer to ask in that case), but you'd probably be better off making sure you have good liability coverage and skipping that $800 expense per property. Besides If the mortgages are in your name putting them in the LLC won't release your personal responsibility to pay them.
I'd also look into if electing as a S-corp for taxes would actually save enough money to justify the hassle it adds (I'm guessing not). It may make the most sense to skip the entities all together. Here's a link supporting this idea:http://dollardisciple.com/3-reasons-not-to-use-an-llc-for-rental-property/
If you have significant personal assets a LLC provides an extra layer of protection and is worth it, but make sure you do it right (Articles of Organization and all that). Whatever the case get an Umbrella policy and ensure each property has enough liability protection.