If you are in search of a standard third party insurance, then taking a decision will not be so difficult. Almost all products offered by the several different insurance companies are very similar to each other. Just decide on the basis of the price and the requirements you need.
On the other hand, if you are choosing a comprehensive insurance cover, that can be very confusing. The basic features as well as the optional features vary and depend on the insurer. Some policies offer to pay for a rental car while others offer you a complementary car to ensure you can move around while your damaged car is being repaired after the accident.
The terms and conditions governing your insurance coverage totally depends on the insurer. One very common requirement is that their repairs must be carried out at an outlet approved by the insurer. Since the cost of service at such an outlet is usually slightly higher than the average establishment, you will be charged a slightly higher premium on your auto insurance policy. Hence, it is very important to analyze the cost before taking a final decision.
No insurance policy ever makes 100 % payment on a claim. There is always a compulsory excess that must be borne by the policyholder when making the claim. Different policies require payment of different amounts of compulsory excess at the time of claim. But you must remember to choose insurers with the best reputations and who are licensed to operate in the state you live.