Well I don't know what you're basing that on. The place recommended by the insurance is pressured to do a good and fast job. A regular joe's repair shop will try to rip you off by asking for more and more money from the insurance company.
Well, let me start off by saying, I know where you are coming from. What you are saying is exactly what insurance companies want everybody to think.
Let me ask you this:
If a body shop can only get the majority of their business by being on an insurance companies insurance list, what does that tell you?
The insurance company adjuster will come into one of these shops and tell them that they will fix the car for $X. If they want to stay in the good graces of the insurance companies, then they will fix it for that amount. Do you think "Shakies Autobody Shop" is going to lose money on these repairs?......nope.
How about a large, well known body shop?:
The insurance company comes in and tells them that they will fix the vehicle for $X. The large shop has somebody on their payroll who knows how to deal with these adjusters. They tell the adjuster "nope, we need more money because of X,Y, &Z". The insurance company will agree to pay for all reasonable repairs.
If after the adjuster leaves and they find more damage (not noticeable during initial appraisal), then they will put a supplement claim in.
They don't need to get business by a "referral list" by an insurance company. They have all word of mouth customers.
I'll take company #2 for my vehicle.