They both have their advantages as others said. It depends a lot on what plastic you print. I have a Prusa MK3 with the magnetic bed and both the powder coated pei and the smooth pei sticker over spring steel. I absolutely love both surfaces and the magnetic bed system. I would not go back to glass for normal printing with PLA or PETG, not a chance. Love how the prints stick and pop right off after. If it stops sticking just use some scotch brite on it and it’s good as new lol.

However, for certain materials like nylon and TPU the PEI is not recommended so I use my old printer with the glass bed for that. I would like to build a high temperature machine that’s liquid cooled. For that I would probably use a boro plate because I think it’s more temperature stable and good for printing PC and other high temp materials.

Hope that helps a bit.