The Excel line of aircraft are some of the best-selling business jets ever produced.  Cessna combined great economics with a stand-up cabin for a big aircraft feel.  They kept the straight wing which allows excellent short field performance and a reasonably fast cruise speed of 420-435 knots up to 45,000 feet.  Operating costs are low compared to similar aircraft of other manufactures.  Auxiliary Power Units (APU’s) are optional on early models and standard for the XLS and newer.  The 560XL series requires 2 pilots, and the cockpit options are a Honeywell or Collins Proline 21 suite on the XLS+.  There is an STC available for a Garmin G5000 retrofit on Excels and XLS’s.  Acquisition prices have historically been stable as demand is high, although all models have shot up after 2020.  This is a staple in many fractional ownership fleets.  Info from the Textron Aviation site XLS+