I've had a couple of different mandoline slicers over the years. I end up cutting myself every time I touch one. Just curious, why do you need one? Is there a specific task that you are trying to accomplish?
Most pros actually use the Japanese Benriner which now comes in 2 sizes. I've had mine for 20 years and it is still as sharp as a samurai sword. The habd guard is simple but effective. Find them at Japanese grocery stores.
I have only ever used the stainless steel variety. Tried a plastic version once but it didn't keep up, I felt like I was going to break it (although to be fair it was not an expensive item, if you catch my drift...) I too have lost some fingernails and a few chunks of fingertip. Luckly I was using very thin settings
I vote the stainless steel varieties much more efficient, if a little scary. But if you aren't cooking in a restaurant kitchen, I would vote for one with a guard that fits over the food or fingers, and a variety of interchangeable blades. If you're going to spend the money, make it as multi purpose as possible, right?
I've seen one type where the blade lifts up when you run the food over it, then recedes to be flush with the body of the mandoline.
Sorry I have no brand names to offer up, I only know what I have experienced, and I believe they were all fairly generic models.
I, too, had tried many plastic versions over the years and been unhappy with them. So my husband blew the big bucks for the Bron for a gift, and I'm quite happy with it. I found the guard clumsy to use, so just use a dish towel to protect my hands. I tried to buy a mesh glove for the purpose, but the company I ordered it from sent me a (much more expensive) knife sharpener instead. Checked the invoice, yes, it said mesh protective glove! So, you don't think I was about to pay return postage? Husband got a new knife sharpener, passed his old one to a friend who needed it, and maybe I'll get around to ordering the glove again some day!
I like the weight and stability of the Bron over the plastic versions, especially when dealing with tough vegetables (sweet potatoes, winter squash).