There's a new design in pizza cutters making the internet gadget rounds. This butterfly-style handle rotary cutter by Progressive is available at Amazon for $7 (plus about that much more in shipping). Turns out that's about the average price for pizza slicers. The purpose of the t-shaped extended handle is to give the slicer some added leverage for thicker crusts. I don't know what it could really offer beyond what you already get with the classic cutter (about which you can read much much more in Scott Wiener's Brief History of the Pizza Slicer). In fact, I think trying to apply equal pressure on either sides of the handle would make slicing more challenging. And the results of not being able to maintain equal pressure seem potentially hazardous in a way straight handled rotary pizza cutters aren't. Maybe it's just how close those knuckles are to the blade in that photo.
My own kitchen isn't even stocked with a pizza cutter. I'll stick with old faithful: