I was always nervous about using regular mandolins (the kind that lie flat across the top of a mixing bowl and you slide veggies back and forth freehand over the blade) because it's so easy to seriously injure yourself with one. I tried one once and the mandolin slid against the bowl, and my fingers were sliding back and forth very close to the blade with only a little finger guard for protection.
I saw a version similar to the one you've posted and it looked much safer, so I tried it and I love it! The mandolin sits on a slant and the legs have rubber bottoms so they don't slide easily. The veggies go into the cup that's attached to the front of the device, and then you slide the blade against them via the knob/handle on top of the device that extends and moves the blade section up and down. Your hands are never near the blade.
I just did a ton of celery sticks for stuffing for Xmas and it took a fraction of the time that it would have taken to cut them by hand. On mine you can even adjust the width of the slices via a dial inside the mandolin. When the celery sticks were sliced down to the length of the cup, there's a insert that keeps pushing them down against the blade until they're all cut. It's super fast, and only needs to be rinsed at the end to clean.
This is the exact one I have.
https://www.amazon.com/gp/product/B08PDNH6YT/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
It's made of plastic, but seems reasonably sturdy, and I've not had any problems with it. You do have to cut bigger veggies in big slices or chunks that will fit the plastic cup, but it's still much faster and you get much more even slices, especially if you have a lot of veggies to cut. The blade is very sharp. I've had it about a year and a half and it's a kitchen gadget I don't regret getting.
So that's my two cents. Hope that helps