i used a super agata for about two years, until the plastic piston that holds the capping bell broke. i had noticed that some of the agata sealed bottles opened easily, and also had a few flat/bad bottles.
i looked for a replacement with a steel piston. i got a g. francis professional bench beer bottle capper from amazon.
i was pleasantly surprised that it seemed to make a much better cap seal than the super agata. however, it is not as easy to deal with bottles of different sizes, requiring adjustment when the bottles differ. after a few batches, i got used to the workflow, and now prefer the francis.
your mileage may vary...