The difference, when the spi is handled right, is such than no crew nowadays sails without a set kite on the downwind legs NO MATTER how strong the winds.
I agree with you - as long as you sail the boat conservativly the spin works great in big wind. In big waves (which often go with big wind on the ocean) we put the crew back on the tramp and stop heating it up as much. I throw the hotstick back in the water and steer off the rudder arm/cross bar connection which gives more precision and speed - important when you get hit with a header puff.
