I had a hard time explaining it to thosse outside the area when I lived there. I usually gave them this summary.
The default Kansas City is Kansas City, Missouri (KCMO). It’s also the largest of the two places named Kansas City. Kansas City, Missouri covers a large area, and there are many neighborhoods in the city limits, north of the Missouri River and far south of downtown, that are suburban in nature. Kansas City, Missouri is also thought of as the nicer of the two. KCMO covers three counties – Jackson, Clay and Platte – and several school districts.
Kansas City, Kansas (KCK) is the smaller of the two places named Kansas City. It’s considered gruffy and downscale compared to Kansas City, Missouri. License plates that you’ll see on cars (or more likely, big pickup trucks) from KCK will have a little sticker reading “WY” on them; this means Wyandotte County. KCK is mostly coterminous with Wyandotte County. Still, KCK has Nebraska Furniture Mart and Cabela’s.
Even though Kansas City, Kansas is considered the bad Kansas City, the Kansas side suburbs (Johnson County) are considered quite affluent. Even though it’s across the state line, Johnson County streets follow the KCMO street naming and addressing scheme. The postal address of Shawnee Mission, Kansas covers several suburbs, including Mission, Roeland Park, Westwood, Fairway, and parts of Prairie Village and Overland Park. Overland Park is considered the large, affluent, dominant suburb, like Plano north of Dallas or Amherst northeast of Buffalo. Olathe is the distant upper middle class boom 'burb on the urban fringe; not much in the way of offices or shopping, but lots of four bedroom, three bathroom, 3,000 square foot houses, four to an acre. Shawnee is considered middle class, and Lenexa is considered quite nice. Leawood and Mission Hills are the most prestigous addresses.
The Missouri side suburbs are generally considered not as nic e as their Kansas City side equivalents, although there’s a few exceptions; Parkville tot he northeast, and Lees Summit to the southeast Raytown is considered redneckish; Independence is growing but still has something of a reputation as a crystal meth stronghold, and Blue Springs is blue collar middle class.
IMHO, the Missouri side suburbs are much uglier than their Kansas side equivalents; Johnson County cities have very strict zoning, sign and landscape regulations. Still, some criticize the Kansas side 'burbs for their sterile, planned community-like appearance.