not all insurance preferred shops are shoddy... just do your research before picking one..
ive had my mazdaspeed6 repaired by a reputable known shop but ended up taking it to preferred shop to fix issues theyve missed and screwed up..
if anything.. you have the upper hand on a preferred shop.. if not done to your satisfaction.. you can indicate that a feedback will be provided to the insurance company..
insurance work is their bread and butter...