Are the flapper cistern valve any worthy? Compared to the good infirm flush siphon, are these replacements any...

Compared to the good infirm flush siphon, are these replacements any good? They look a bit weedy near a thin tie up and use the same technology as the dual flush which are rubbish. Have you used these as a replacement for a siphon instead of of late changing the diagraphm? Is the flush power any better or worse?
Answers:    the flush is like but they can scalegunge up where the flap sits on the trademark so not great imo