The Hudy has a giant motor in it that will let you cut down tall tires in a single pass. I believe that's the main reason people like it, though it's also very high quality in many other ways as well.
In hindsight, I wish I would have purchased the Hudy. I mostly only true my tires when I'm cutting them down for the first time, and doing it in stages is a big hassle. Plus, the one I have has a lousy depth gauge.
Thankfully, with most tires coming pre-trued, now, I can set my cheaper truer to my final depth, lock it down, and do everything in one pass. So the pre-trued tires have made the situation a little better. I still regret not spending the extra money on the Hudy, though.