Two years ago I went from the Savannah 2 to the Comfort Shell. While I really liked the Savannah 2, with and without the liner, the Comfort Shell is the best of all worlds. I just spent two weeks riding in southern Europe with weather ranging from two straight days of 50 degree rain in Switzerland, to 85 degree days in Germany. Perfectly dry in the rain with just a light polarfleece and very comfortable in the warmer weather with the vents open. The jacket is completely waterproof and yet vents very well in the summer. Just yesterday, I rode in 105 degree heat, and while hot, the jacket vented extremely well through the vents and the material. Since the material of the Comfort Shell is not Gore Tex or spayed with any waterproof coating, the waterproofing remains constant and there is no need for zip-in liner. Check out the BMW site for the details on the material.