Choice has tested all sorts of cleaning products including toilet cleaners but seems to have stepped around a genre of product usually called toilet fresheners. Based on the shelf space they have at the grocers they must be profitable lines as well as good moving products.
Many of us use them. In my experience some fall apart more quickly than others, and the claims about cleaning, foaming, scenting, and so on are all over the place. It would be interesting to read an objective Choice commentary, as well as a test not a paper comparison, against their claims.
For clarity, the products include the ones that go in the cistern to slowly dissolve (apparently frowned on by the plumbing community) as well as those that hang in the toilet. And is a periodic swish with bleach or a cleaner as good or better a solution to ‘the problem’? Are these essentially vanity products that suck dollars from consumers or do they work as advertised?