More manageable than a large SUV and roomier than a small one, the mid-size SUV is many people's idea of a just-right solution for their varied requirements. As kbb.com editors note in their choices, these days there are two types of mid-size SUVs on the market—those based on car chassis (called "crossovers") and those based on truck chassis. Of the two, the crossovers are gaining popularity while the truck-based SUVs are slipping.