I've had my Kapex a couple of months now, and here are my thoughts -
Accuracy is dead on, despite the Kapex not living in a shop. It gets moved a lot. The big thing for me is the bevel mechanism. I do a lot of wide baseboards in the neighborhoods I work in, so cutting a 8-9" baseboard flat on the table requires a good bevel system. The front-mounted handle and large angle scale make that very simple.
Dust collection (with a CT) is also better than any saw on the market, in my opinion. It's also 25 pounds lighter than a comparable slider from DeWalt or Makita.
There are some drawbacks, as with any tool. The miter gauge that comes with it is sometimes useful, but mostly gets in the way. You have to slide it back and forth in it's little home in the saw base to clear the table when doing miter cuts. The blade is not a standard 10" blade, so throw out all your existing blades, and don't bank on picking one up at the store if you need one in a pinch. Always have a spare, because even ordering from Amazon Prime you won't get it for a day or two. (unless you have a local Festool dealer).
UPDATE
As for the rant above, I am one of those TV carpenters. Not all of us are just "pretty boys". I wouldn't have made it to over 300 episodes if I was just a pretty face. Many of us have years of actual carpentry experience (25 years experience, in my case) and enjoy the challenge of doing a project in a day or two while set up in a tent in someone's backyard. I do agree with you that it's not a normal job site. It's a normal job site with tighter deadlines, more bystanders, several cameras and microphones in your face, and a designer hovering over your shoulder changing things by the minute. And it's pretty damn fun.
To bring it back to the subject, I love all my Festool stuff, but I have to use many different brands of tools in order to satisfy contracts with advertisers or network rules. Sometimes, all labels have to be stripped entirely. I can tell you from my experience, the Kapex is the saw to have. In the last 3 years I have used DeWalt, Bosch, Kobalt, Hitachi, Makita, Milwaukee, and RIDGID sliding miter saws, and the Kapex is by far the most accurate and easiest to move around.