She's a decent B-lister. Certainly not "awful." Only Pub who could've won this is Latham IMO.
Joni Ernst seems like an analogue to Chuck Grassley. They are both strong conservatives who had to take down someone who seemed like the establishment candidate. This race probably tilts in Braley's favor, but I think Ernst can still win this if she plays her cards right.
At best, Latham would probably be tied with Braley or behind by a point, meaning the dynamics of this race might look more like those in Colorado.
A better analogue is the Sara Palin of Iowa.