I've used them and had good success. I mostly keg now, but occasionally I'll want to bottle a 6 pack of whatever I made. So as soon as I keg (before carbing in the keg) I pour off 6 bottles worth and drop the tabs in.
My situation might be a bit different though. I usually let these bottles sit upwards to a year before i drink them, so I'm sure whatever needs to be eaten gets eaten. I don't have any chunks and my carbonation is good - if anything a little too carbed. But again, mine sit for a long while, so ymmv.