While I agree that porper insurance is a must and can be a quality way to operate your rental biz, there are a few extra advantages to the LLC format.
1. How do you know how much of an umbrella policy to get? 1 million, 3 M, 5M? What if you choose 1M and the law suit is for 5M? Plus the cost of going really big to CYA could be in excess of the cost to simply have an LLC.
2. Your identity: While an LLC does not give you full protection from others knowing your name and who onws the LLC, it does allow you to bill your tenants under your LLC name or other corporate entity making it a bit more professional and most tenants will not take the time or have the knowledge to research who owns the LLC. This way, your tenants are not paying Joe Smith, but JS, LLC
3. While there are costs involved in starting and operating an LLC (state fees, accounting costs, etc), these costs can be spead over a few properties making the cost very little per property (of course I also recommend not having to much equity exposed with multiple properties in an LLC)
4. LLC gives you one extra layer of protection in addition to the insurance. As an investor, I look to add as many layers as possible for protection. Why not? Of course the liability protection in an LLC is only one way protecting you form the asset, but not the asset from you.
While it can be argued either way, I too choose to use entities for my business.