I bought this as I am always fiddling around hanging pictures & photos in our house. The house is 70 years old, and the takker pins went into the plastered walls without much problem. Took a few goes to get a feel for thumping it with the 'heel' of my hand.
We got a big, heavy, 2 metre long mirror for the hallway after redecorating. I thought I would give the takker a shot (unintentional weak pun). I put in 2 Takker pins at the 2 metre span. I tested them by hand, and they seemed pretty solid. Then gingerly tried the mirror. It seemed pretty solid on the bracket loops. It is still there 2 months later, so the claim of 10 kg per pin has passed the test with me.
It is time to buy more takker pins for a few more jobs. I have a couple of times recently noticed pictures sitting around friends houses, and offered to hang them for them. It is a job that many are 'getting around to', and it is nice to be nice by helping out!
The device is not perfect, but I would feel it quite a backward step to go back to banging in nails. Overall - I think it was worth the money.