The limited liability company will provide protection from contract based debt against personal assets of the owner of a single or (multi-) member LLC, assuming no personal guarantees have been made and no fraud was conducted by the owner. Contract based debt for a rental property could include utilities, general contractor repairs, and appliance purchases. These creditors would likely be limited to recovering their debt from LLC assets. Personal guarantees will likely be required for mortgages taken in the name of a newly formed LLC with no credit history.
The LLC will not likely provide personal asset protection from non-contract based debt, like negligence and fraud. A non-contract debt originating from an act or omission that the owner of a single member LLC, or one of their agents, participated in can be recovered from the personal assets of this owner. If you are the owner of a multi-member LLC, and can prove in court that the act or omission which caused the non-contract debt is independent from your duties to the LLC, then your personal assets are likely protected from this debt.
Yearly fees for an LLC will be about a hundred dollars to your secretary of state. Multi-member LLCs, in some states, will pay their state an additional entity tax based on yearly profit, which, in Connecticut, will be partially credited back onto your state individual income tax return. Multi-member LLCs must also file a separate entity income tax return but will be taxed on the rental profit on their individual income tax returns. Single member LLCs will have no change in income tax treatment or reporting of rental profit.
Yearly premiums for hazard (or homeowner) insurance on a rental property (aka landlord insurance) is higher than on a residence. But, merely transferring title of the rental property to an LLC should not change your yearly insurance premiums when compared to insurance on an individually owned rental property.
Your individual name and residence address will not be hidden from the public, in Connecticut, when you create the LLC or when you title rental property in the name of the LLC. The local land records will show the LLC name and, if there's a mortgage, the mortgage will show the LLC owner's name. The LLC yearly "report" with the Connecticut Secretary of State will show the owner's name and personal residence address unless you can show good cause that publishing your residence address would put your personal security at significant risk.