After you are involved in a car crash, you need to get your car fixed. For most people, this is their top priority. They want their car fixed - and they want it fixed now.
Most insurance companies are going to go out of their way to recommend a body shop to you. They will offer this as a "convenience." You use their shop and they pay for the repairs directly to the shop, they "guarantee" the work, and you think it is easy.
In my experience, do NOT use a shop recommended by the insurance company. There are a variety of reasons why this is bad. First, the shop has usually agreed to a discounted rate with the insurance company. Second, if a dispute arises about what needs to be done to properly fix your car, the shop is not going to advocate for you. The shop is going to want to keep the insurance company happy. After all, your car will probably only be fixed one time. The insurance company, however, will be sending hunreds of people to the body shop. So who does the body shop want to keep happy? Third, some shops will use non-OEM or LKQ parts to fix your car, even if it means spending hours to make the part fit properly. Is that really better than getting a new part from the manufacturer? Probably not. While it may be appropriate in some cases, who is going to tell you if it is appropriate in your case? Not the shop that is getting referrals from the insurance company.
Find your own body shop. Talk to friends and family for referrals. Go online and read reviews. While it is important that you get your car fixed, taking an extra day to find the right shop for you is more important than going with the easy route of the insurance company recommendation.
By the way, any good shop will guarantee their repairs. Don't fall for that trick!