Kitchen Gadget for Chopping Onions and Garlic

It seems that many recipes call for chopping onion or garlic which can be time consuming. I have a large Cuisinart that is useful, but at the same time quite a lot to contend with depending on the size of the recipe. This product from Williams Sonoma is called the "Vegetable Chop & Measure". There are currently 84 reviews which for the most part are very favorable. I just got through watching the video. Tell me what you think if this is a worthwhile kitchen gadget or not? It did meet my first requirement that it is dishwasher safe! Price: $30. Available: here.