I'm considering upgrading my old ender 3 and it looks like the prusa MK4 or bambu labs p1s are the current best options out there.
I like the bambu labs for the fast print speed and x/y print bed. I also love the idea of the AMS - it would be awesome to print in colour! But being closed source puts me off a bit as I currently use octopeint and obico to monitor my ender 3 which, as far as I can tell, Is not possible to use with bambu labs. Also having to upload gcode to the cloud is not ideal.
The prusa however is great because of the open source nature. However the slinger bed and slower prints are putting me off. I have also read that the mmu can be temperamental at best, so printing colour may not be an option?
I was in the same position two months ago and decided to go with the Prusa MK4 kit with the enclosure. So far I'm happy with my purchase. The deciding factor for me was lastly the loudness of the device because I wanted to use the printer in my apartment. Reviews said that the printer is relatively quiet and I can confirm that. If the door to my "printer room" is closed I'm not able to hear it.
Some points about the MK4:
Positives:
It prints very fast with the new Input Shaper firmware
I can control the printer via LAN and WiFi (or print directly from a USB drive)
Excellent print quality
Open Source and spare parts are avaiable for a long time
Negatives:
Maintenance is complicated after installing the printer in the enclosure. You can only access the printer through the front door which makes reaching the sides of the printer difficult and removing the printer from the enclosure is not easy as well because you first have to disassemble the display unit.
I dont' have access to a Bambulab printer so I'm not able to compare both the Prusa MK4 and the Bambulab P1S. Nevertheless, I'm happy with my printer and can recommend it.