I recently purchased a cheap textured PEI build plate from Ali Express. It was about half the price of a Bambu Lab plate. Its steel component is also about half as thick as the Bambu Lab plate. I couldn’t praise it hightly enough for printing PLA and PETG, as it holds the model far better than the Bambu plate at printing temperatures but let’s go very easily once cold.
I’ve also used that same plate for printing some ASA parts, each less than 100mm or so in any direction, with fantastic results. Today things went somewhat less well when printing an ASA part that’s 200mm square. After printing about 15mm high the part started warping a little.
Normally that would be just annoying but this time it remained firmly attached to the build plate, so that plate simply started bending. As a result of that bending the magnets no longer held it in place and the build plate and the model started skating around. Unfortunately, I had recently “temporarily” disable plate location detection and had forgotten to turn it back on. It’s just lucky I went to the workshop where the printer is and saw it.
In conclusion: These plates, or at least the one I have, are fine for smaller ASA models, as well as PLA and PETG of any size, but beware of using them for larger higher temperature printing.