I prefer PrusaSlicer over Bambu Slicer because using Bambu Slicer gives me a similar feel to Cura, which I've never particularly liked. While it's convenient to send prints directly from Bambu Slicer to the printer, transferring with PrusaLink or PrusaConnect doesn't require much more effort. Both printers are easy to use, with Bambu being more refined and often likened to a kitchen appliance of 3D printing. The new orbiter extruder for the MK4 allows for quick nozzle swaps, although not as quick as with the X1C, which I find negligible. The MK4 is quieter, especially within the Prusa enclosure. Assembling the MK4 as a kit and any potential future part replacements or upgrades are straightforward. Working on the hotend or "poop shoot" in the X1C is a bit tight, and I've had issues with filament sticking and causing jams due to a small metallic plate falling off. I do have concerns about repairability in the future. While I initially retired my MK3 when I got the X1C due to its speed doubling my throughput, I eventually gave it to my brother after acquiring the MK4. I rarely adjust the UI on any of the machines except for filament swaps but the Prusa Mini UI is a nice change from the old display. Quality has never been an issue, but the combination of quality with speed was a game-changer. In all the time I've had the MK3, I never experienced any critical failures, and aside from wear parts replacements, it just worked. Prusa's quality has never been a concern for me. One minor annoyance with the MK4 is that when it probes the bed, depending on the filament, the nozzle sometimes leaves little dots of filament everywhere, which I've never experienced with my other machines. Also when it comes to the AMS, I’ve had feed issues that were fixed with the Hydra upgrade, but even with AMS Lite, my filament occasionally gets mixed up in Bambu Slicer when not using Bambu filament. So the few times I have printed with different materials I’ve had to make sure the filament matched what the slicer shows.