Road trip question?

We've done both. I asked dh and he said it depends on where you're coming from.

eta: He said other than the mountains going through Colorado there isn't really much difference. On I-80 you have to go through some mountainous areas but not nearly as much as on I-70. 

I remember nothing, personally. I was the passenger. 

I've done both but for these two states it doesn't really matter. What matters is how it affects the rest of your trip. Isn't one of them going to be either to far south or to far north at a later point in the trip?

We really liked the Great Platte River Road Archway in Nebraska. The kids had fun going through the maze there. 

This. I only did Kansas once and never again. There is absolutely nothing along that road except signs saying "Do not drive into smoke" and " Do not pick up prisoners".  God forbid you should have to pee or eat.

Now that (for the most part) they are both 75 MPH it just depends where you are starting and ending. Personally, I hate the drive from KS to Denver. But, I also despise having to leave I-80 to go South after Lincoln.
And... I do hate to drive through KS City so if I can avoid that, I'm happy too. Unfortunately, I've made both those journey's too many times so it depends on my mood, and where the final destination is. I have always thought that there were more highway patrols in KS which can be good or bad depending on whether you need them or not.