I bought a De Buyer Mandoline. I paid 120 Euros for it at an outlet store. It was an impulse buy because I live fairly close to the De Buyer factory and really didn't take the time to research and find out if I was getting any kind of good deal at all. I'd been thinking about getting one for awhile and had just returned from vacation which put me in a spending mood.
Even though cutting a variety of julienne / crinkled vegetables looked fun, I wanted it mainly for two things: An adequate method of cutting french fries, and a quick way to cube cooked red beets. Well, for the first part, the mandoline is great. You can make french fries that range from small and thin to tiny and skinny and it's quick and effortless. One caveat: it can never cut the very last slice, it... ejects it, or kind of. If it gets to the point where the slice is too thin, the food grabber can't push it through the blades. As for cubes, I think I've been had. The only place where De Buyer has published that the mandoline can dice food is on the outside of the mandoline box. There's no directions on actually making it happen. If it were theoretically possible, it would involve re-slicing each julienned slice perpendicular to the first cut but like I said, the pusher has to be higher than the blades. In short, I think it's impossible and I'm a victim of false advertising.
Am I happy with the mandoline? I don't know yet. I admit that it's very high quality, professionally constructed equipment. It makes short work of any slicing you'd want to do in huge quantities. The blades are like razors. Everything is dishwasher safe. So far, however, I don't think it was worth the layout of 120 Euros.