Cleans well, depending on surface.
I bought these for a project that unfortunately did not clean up at all with the Magic Eraser, but I've subsequently used it on other surfaces around the house and it has cleaned up a few things that were difficult via other methods.  It took some black marks off of a wall that resisted removal by other means, and it has also cleaned some soap and calcium deposits out of a bathtub surround that other cleaners (including Comet) could not tackle.  These will not clean everything, but on the things they do clean, they work well.
Rating: 5 stars