One consideration is whether you are doing this trip during the cruise or if it is a post-cruise. If it is a post-cruise and you go with a local operator that may be a great idea. However, if you are planning this trip during the cruise you need to know that if you book through the ship and for some reason it runs late in getting you back, the ship will take care of you. If you book it on your own and there is difficulty, the ship is not responsible. I agree with Doug that this appears to be a standard price. While I do not tend to do lots of ship tours, there are certain places and tours that ship tours are the way to go.