With a couple of notable exceptions, I generally don’t recommend “kids tablets,” because they often skimp on specs and performance compared with Amazon’s Kindle Fire line. Choosing a worst of the worst in this group wasn’t easy, but the Vinci MV 7 deserves this dubious distinction. For starters, the 7-inch display shows visible gridlines, and the battery lasted only 3.5 hours on our tests. That’s awful. Add in sluggish performance and a shocking lack of parental controls (this is a kids tablet, right?) and you have to wonder whether Vinci’s URL of vincigenius.com is a twisted joke.