All three as far as I'm aware are good sea boats, however I can tell you more about the differences of the OP and Destroyer.
OP is a different hull entirely and may or may not have a wider beam depending on individual boats, due to different sizes being available, usually though, the OP is wider.
The hull itself on the OP is far more complex (therefore more expensive) with chines that you will see running from the front. These will tend to push the water from the chop/waves out and away from the hull more so than the smooth Destroyer hull. It will also have a quicker hole shot as there is more uplift, (ie get on to the plane) and will not sit down/sink as much when fully loaded. Consequently, the hull is faster and dryer but more twitchy at speed as it sits higher up on the plane. The Destroyer is a highly rated hull in its own right and will slice through small choppy water theoretically more smoothly, but arguably it is hard to tell the difference with a boat over 6m long.
Check this for the history of the hull http://www.ribmagazine.com/site/inde...=134&Itemid=84
The OP is a very well known hull and a 6.3m version is currently being used for the Gore Tex Arctic challenge. Says a lot really, and we have one, so I suppose I am biased. Featured in this months ribmagazine along with our goodselves on the Menai rib rally in our Yellow OP!
Plus if the OP has heavy duty tubes, it is more fitting for your fishing(hooks) and diving(wear and tear dragging people in)
Hope this helps, though I believe any of the three are fairly suited to your needs.