We used to use dishwashing tablets, but they used to over soap the dishwasher and clog the pipes etc.
They are often featured as OzBargain specials (such as the front page today).
About a year ago we spoke to a dishwasher service repair man from Fisher & Paykel who was servicing our dishwasher and he said not to use the tablets. The contain too much powder and block the pipes as well as leave residue.
He recommended to use a powder and only a tiny amount of it per load (about half or quarter of a teaspoon) as well as some rinse aid.
We've been doing this for over a year now and have had fantastic results with no clogging and no residue. Plus it is SO much cheaper even then buying the tablets on a bulk-buy special.
So, are tablets some form of elaborate scam sold for convenience that we don't need?
I remember choice did a review of the dishwashing powder few years ago and found generic Coles branded dishwashing powder to perform the best. Since then I've been using it with no fuss.