The biggest disadvantage in my mind of the Prusa MK2/3/4 printers is they use the original i3 design. It's a good design, and very simple to build, maintain and program. But it limits the print speed due to the amount of mass that has to move, particularly in the Y axis. The entire bed has to move which induces vibrations at higher speeds.
Newer printers (including the Prusa XL) use a CoreXY design, where the extruder is controlled in the X and Y axes by belts, which results in less mass that has to move, and allows the printer to print much, much faster. In the case of the Bambu Lab printers, it can be two to three times faster for a similar print quality.
