Well I have been using one for years. Main purpose is bird and wildlife photography from the truck when I use it as a blind. To be honest I am pretty happy with it. According to the shooting angle needed I can rest it on the door window frame or raise the window partially and shoot it that way. My only complaint I guess would be sometimes I will fall off the side of it when using my monster Nikon 800/5.6 lens. So sometimes a bit more sureface space might be nice. Maybe use a grippier material all over. There are times I use it in various positions off the hood of a vehicle and sometimes it can slide on the surface. Since these are quick grab shots usually it would be nice if the bag wasn't moving as I try to get the shot before the subject bolts.