Out of the 2 boats you mentioned, I don't think you could go far wrong with either! I'm probably biased as I have the Tornado 750
, but I rode on an osprey vipermax 7.5 with a 300 e-tec at ribex a couple of years back too, and its a great hull also. I would say the Osprey was marginally more comfortable a ride perhaps? Hard to say, but the Tornado has a Higher Bow which i like (un-stuff-able in the 7 years I've had the boat in big Hebridean seas) and also I didnt like the way you cannot walk around the console on the osprey, you have to walk on the tubes to pass around the console. (on the double console one i was on anyway) The tornado seems larger inside space compared to the Osprey.
But like i said, both very good boats.