For a mini-food processor/chopper (this won't help with slicing) I recently bought a Ninja that comes with six bowls. I thought the six bowls was overkill but I love this thing! It chops carrots, onions, garlic, you name it, evenly and I don't get "mush". Each bowl has a lid so if I chop onions I can use some of it, put the lid on, and put it in the fridge. The bowls stack so that is convenient, too. I bought mine at BJ's and haven't seen this particular combination anywhere else. I bought the version with the tall drink cups for smoothies last year and really like that, too, but it wasn't suitable for chopping veggies.
I think the secret on the even chopping is the two-level blade.
I've been wanting a mandoline so am glad to hear about the Oxo.