The bathroom sink and the stainless stove top have always been a mess to clean up - especially hard water stains. I've tried several cleaners with mixed results. Even the best required lots of elbow grease.
Last week I bought some "Bartender's Friend" cleanser which is supposed to be non-scratching. It contains oxalic acid - which will cut rust stains on porcelain. I'd used a similar product called "Zud" years ago but haven't been able to find it again for a long time. OMG - this is even better! You can make a paste of it and leave it on the big crusty water stain that forms regularly in the bathroom sink - then with very LITTLE effort, it scrubs the stain right off! Ditto on the stove top. It even takes off the brownish tint that stainless pots and pans can get from a gas burner.
Last experiment? It works cleaning the fiberglass shower and the glass in the door. I haven't tried it on the aluminum frame around the door - and in fact have specifically avoided this area. I'm not sure I'd use it on a softer plastic such as the toilet seat - and with the paper thin Safari laminate surfaces I wouldn't use it there either. I don't hate to clean, but I want to get it done and move on!
I'm going to throw out about 90% of the other crap I use to clean!
Downsides? The label warns not to leave a paste on a surface for more than a minute - so on some surfaces it might be corrosive (gee with an acid as an ingredient, really?). It smells kinda nasty in a mild way and doesn't rinse out of cleaning cloths easily, but a disposable paper towel or shop rag should solve that.
Paula