What do you want to do with your computer and Ipad? What are your preferences? Neither combination is objectively "better" than the other, it all depends upon how you're going to use it and what your preferences are.
I use a macbook air and iPad mini myself. I typically wear a jacket, which allows me to carry the mini around about in a jacket pocket as easily as I carry my cell phone, yet it's just big enough for reading pdf's in portrait mode. While a larger device might sometimes make web browsing more comfortable, it's worth it to me to have a device that can go everywhere with me, and that is so small and easy to carry. Besides, if I want a larger screen, the macbook air can slip into my briefcase nearly as easily as a full size Ipad could.