Love these.  Wasn't sure how they would hold up in the dishwasher, which is crucial for me as I already have more than enough items to hand wash, but they are doing great.  They really do make a seal and you can pick up the bowl underneath by lifting the tap in the center of the disk (?) if the contents are not too heavy.  Had fun playing with them with a three year old who was fascinated with how they would pick up the bowl... or seemingly stick to the counter... before their first wash.  She was so proud showing me how if you pull straight up it's stuck good, but if you pick it up from the side it's like it was never stuck at all.  I'm sure if you damage the smooth under-surface, it's game over, but no problems so far.