I live in the Midwest. What are the disadvantages to using the Ascent on rolling and flat terrain? Would this model be a good overall snowshoe or would it be overkill for hilly terrain?

In the Midwest, for rolling and flat terrain, I would avoid the any "ascent" snowshoe, these were engineered more in mind for mountaineering and have rugged crampons on the bottoms that grip tight to steep uphill, but for flatter terrain, a snowshoe with more flotation and less grip would probably be more ideal. On the whole, these are decent, lightweight snowshoes meant more for biting into step windslab/shallow snowpack rather than floating on lots of powder. Look for a snowshoe with an aluminum binding, as these generally have more flotation in deeper snow, with minimal crampons (ie only a toe crampon) for moderate uphill portions.

These shoes are great for hilly terrain. I spent several days in Lassen climbing hills in these, and they were fantastic. The ascenders are a big help for uphills, and traction was always top notch.

Can't really think of any disadvantages... unless you are doing jogging in snowshoes, then they make sport specific versions and this one wouldn't be comfortable... This would be overkill for general use... the crampon is designed specifically for icy/variable steep terrain...