I've been through Limon only as a means of getting further west or heading home; never stayed there.
Many KOAs are "Journey" campgrounds. Those KOAs along the interstates are often just a place to stop and sleep; not that much better than a W/M parking lot, if even that. The most I hope for in these places are clean RR facilities. And honestly, even other brands and private campgrounds are not much different when they are located right by the interstates.
KOA has redefined how they delineate the campgrounds:
Meet KOA Journeys, KOA Holidays and KOA Resorts – three helpful ways for you to find just the right KOA for your family’s next adventure.
koa.com
It used to be that the KOAs were either Journey or Destination. Now they have they three; Journey, Holiday and Resort. It is my assumption that the KOA mantra for these three types of campgrounds is different; Journey KOAs are probably not held to the same corporate standards as the higher-end campgrounds. (I realize they are pretty much all franchised, but I'm sure there are criteria each campground has to meet based on their category type). The Journey KOAs seem to have a fairly wide range of how nice (or not) they are. The Holiday campgrounds are held to a higher standard, and the Resorts even more so, therefore they are given less leeway; they are expected to hold a much nicer standard.
For example, one place we like to camp is Buena Vista, CO. The KOA there is a "Journey", and so they have dirt roads with barely much gravel at all, and the sites are pretty much the same as well. But the location is good for what we want to do, so we stay there anyway. The RRs are reasonably clean and the laundry is decent, so that's all we need. But the infrastructure of the campground (roads, sites, wi-fi) are all "so-so" at best.
We've also stayed at Grand Junction, CO KOA. It's a "Holiday" campground. Much more in the way of amenities and overall nicer place. Everything is clean and well groomed; good wi-fi; nice pool; etc.
We've not stayed in a "Resort" KOA ever.