I have owned my H4D-40 for just over three years.  I often feel like I am not shooting it enough, but let's face it, it's big and by the time I load up the camera and a couple of lenses, it's going to be a long day.  I have an RRS L Bracket on mine because I mostly shoot it off a tripod, rather than handheld.  Over the holidays I rented an H5D-50C from Henry's Rentals to check it out.