You mean Sanibroyeurs, the toilet that mixes up the contents of your toilet bowl so it will pass through ordinary plumbing pipes?
They can indeed make a lot of noise when old, badly installed or having suffered from bad maintenance. Over the years these broyeurs have been further developed and the level of noise is reduced, but it remains the main difference with a ordinary toilet. But they're the only solution when you want to place a toilet in a rather confined space, i.e. where there's no room for a 10 cm diameter tubing. And you've got to be more careful with wat you throw in your toilet bowl. Especially if there are little kids in the house who are known to throw things like toilet-paper rolls etc. into the toilet.
They are relatively expensive, and a good installation should be done by a pro, unless you are a gem in DIY yourself ;-)