After trying a magnetic sheet on the print bed I hated it for curling up with bigger prints. I went back to the original fibreglass and stickie bed. The one thing I always hated about the original bed was using those damn spring clips to hold the bed in place, especially the ones at the back. So I designed a simple bracket printed in PLA with no infill that is glued onto the bottom of the hot plate. Two of them spaced apart on the back edge. Glue is a common Chinese rubbery contact cement type B-7000.
The bed slips into the grooves holding the back of the bed in place and then use two spring clips for the front edge.