With a short Class C you get a little easier parking in malls etc., except for the height and width which is about the same regardless of length. With a 27 foot or longer you can get a rear bedroom with RV Queen sized bed plus overhead bed for kids and usually a convertible dinette or jackknife couch that converts to a bed. Adults with any knee or foot problems quickly tire of climbing up and down a ladder in the dark and trying not to awaken their spouse. 27 footers and longer have a lot more cargo and cabinet space which is good with kids stuff and, etc. Rehearse sleeping, going to the bathroom, showering, cooking, etc., when looking at various lengths and floor plans. A 27footer handles almost the same as a 22-24 footer. Is your driveway long enough? Slides are nice if they don't block access to things when retracted, they add weight and potential for mechanical and water leak problems. Don't be overawed by a 27 footer vs a short Class C that is 3 feet longer.