Is it advisable to have a storm contractor present when your insurance adjuster is calculating the damage?

My home received hail damage this past wkend...siding is pitted in many places, broken and cracked in other locations, there is possible roof damage and places where softball sized hail hit wood. It cracked the windshield of a car parked in my driveway as well as many dents in the hood and the top of the car. My neighborhood is now flooded with storm contractors that want you to hire them to do the repair to the house. Each of them are offering to be present at the time the insurance adjuster is here calculating what they will cover in damages. Is it a good thing to have a professional contractor present at the same time as the adjuster, or would that make it worse? I've never had a home claim before, so this is all new to me. I wouldn't even know what company to call to do the repair, but some of these guys have great information that I am learning from. One company tho, stated that I would have to turn over the insurance check first, before they did the work...I am not privy to that at all. The next company said that was not a good policy and they would not expect any of the payment until the work was done. My main question is: Will an insurance adjuster be ticked off that a contractor is present, or do they support having one there? Seems to be the going way with all these "storm chasers"......they all give free estimates and want to be present with the insurance adjuster.