It depends on the fold. There are lots of ways to use them so that they fit different sized babies.
If you get smalls, 27x27 or so, you can use an origami fold when they are smaller, or fold in the corners so that your flat is half sized and do a kite fold that way.
When they are bigger, you can use a regular kite fold. You can padfold a second one into the middle as a doubler for more absorbency. Or just do your fold with two together.
You can padfold and lay into the cover, similar to trifolding.
You can fold into a rectangle and then use like a prefold.
There are way more folding options than I have mentioned.
So I would say they are much more versatile and adjustable than prefolds!
Plus they wash and dry awesomely and double as blankies, burp cloths, changing pads, and nursing covers.