being a auto body tech i will agree with this 1000%
they have the worse claims processes i have ever experienced. they write extremely low pay estimates based on pics. them when you file a supplement. they will only approve additional repairs after a adjuster visits your shop in person. after they visit they again write extremely low pay estimates. their estimates usually include prices for parts from several states away where shipping of parts is not included with the price quote.
i would assume they do this to steer the cars to their direct pay body shops where they can control prices better. the shop where i work isn't one of those shops.
i myself tell people i wouldn't use geico insurance if someone else paid the premiums.
whenever possible the manager tries to not work on cars covered by geico insurance. it isn't worth the hassles to him or the shop.

allstate isn't much better on writing good estimates, but at least they have a supplement process where you talk with the adjuster over a cell phone. you can show pics of the damage with the phone and get approval quickly. .......disclaimer. i don't handle any part of the claim process. i only repair the cars.

OK rant off