Basically, the Baby Bjorn is probably expensive, but I think that the price-performance ratio fits.
In a furniture store I've seen much cheaper stool, however, the only 4 tiny feet had untendran. Sooner or later, so goes a little feet lost and you can throw away all the stool. In contrast, the Baby Bjorn the whole bottom is slip resistant, otherwise it is processed fairly dibasic.
Weight is indeed to find any (according to the homepage it's just meant only for children), my 75kg but he holds out easily. A few children, he should therefore stand and then the price into perspective so again.
For Grandma I incidentally also now an ordered.