With either one you choose, finding your favorite tire pressure will be a bigger factor in how they handle, how long they last and what you think of them more than the size of the tire, itself, IMHO.
I don't think there is a best choice here and think the only way you'll notice a difference between the two tires is if you personally experience them both for comparison purposes.
The wider tire will inherently be a little "softer" than the narrow one and should be slightly larger in diameter.
I will admit that if they offered the Shinko 244 (same general tire category as your chosen K270) in a 3.25" size, I would probably throw one on at my next tire change just to see what it's like.
I wouldn't gnash my teeth much over the choice in the two sizes. I think this decision calls for nothing more than a coin flip.