Do they all wear down? Thus giving an uneven edge on chisels etc…

Ceramic and diamond ones wear down far slower than traditional stones, but otherwise yes. Some Japanese waterstones wear down just by looking at them!

Any recommendations?

Flatten your stone on the garden path before sharpening your chisels 😉

You need to develop a technique that wears the stone evenly. Figure of eight.

Japanese waterstones for me, I have tried just about every sharpening stone on the market and definitely prefer to sharpen with a waterstone.
If you do nick or scratch them or they start to dish out a bit then you can easily flatten them using wet and dry paper and a piece of glass, just takes a few minutes.
If you look after them you should get well over 10 years or more from a decent stone.
I have a set of Spyderco ceramic stones that don’t wear at all, they are however bloody rubbish.

Figure of eight is best by far imo. But I can’t be arsed and I hone edgeways, which is never affected by uneven wear of an oil stone. Although uneven wear has never been a problem for me since I switched to diamond stones.

out of interest what’s the best way to get a good edge on a kitchen knife for normal use (not for shaving hairs off my hand) I have tried a steel and several pull through sharpeners but not had good results.

The best way I have found is Japanese water stones but finding the best ones for your knives and learning how to use them properly is a costly exercise. Only really to be undertaken if you have high hardness Japanese style kitchen knives.

Always done my knives with a steel and never lost an edge. ….but I’ll put them over the steel fact time before Iuse them. Some of my kknives ( Victorinox ) are 30+ years old.