I bought one of these a few months ago to use with my new fryer. It came with one blade which produces quite thin chips but not titchy fries. I couldn't get on with it at first. However, after a few tries, I became more confident and happier with the product.
To begin with, I tried to put potatoes through that were too big and it resulted in having to stop and pick the potato out of the chipper each time. I nearly gave up on it. I suppose I thought it was a totally preparation-free gadget. Then, I started cutting each large potato in half and making sure carrots, parsnips, sweet potatoes etc were sectioned so they would easily go through without getting stuck. It takes so little time to just slice a large vegetable in half, but so much time to pick out one that you've tried to force through in the hope of saving time. Also, it helps to place the veg against the blades and push a little before using the lever to carry on the job. This helps to position the veg where you want it while you push so it doesn't slide to the side and clog the blade. You can push through unpeeled potatoes and other veg as the blades are sharp enough.
Now, I use this chipper every day and love it. I just make sure there's enough space in front of the chipper before pushing through everything I want to chip so I don't have to stop and fuss about with what I've already chopped. You soon get used to the action needed to successfully and easily use this product and, provided all your veg is already cut and ready, you could stand there chipping all day without a problem. When you first start using it, it does feel like you're going to break it if you press down too hard because the lever is made of plastic, but you wont if you use the right action. It's stronger than it looks.
I have only given this four stars because the suction cup doesn't work properly and the blade pops down and out of position sometimes. However, if I hold the unit down with one hand and push the veg through with the other, it isn't a problem that would make me stop using it. This happens very rarely, I might add. Also, the rubber suction cup still helps you to stabilize the chipper, so it's not a total waste of time.
Overall, I would recommend this chipper if you don't mind using a knife to firstly cut a large potato or other veg in half. That's all it takes to make this chipper so easy to use and still makes it a far quicker way to chip larger amounts of veg than using only a knife.