OMG PTAD XD. Lol, what a lulzy stage to fight on. But yes, it is a stage that should be talked about... And a stage where we should explore all the lulzy things that can happen here.
Overall, PTAD is a good stage for Pit, while at the same time, not a really good stage for Pit. Pit has great advantages here, but they also come with a truckload of risks. Pit has great mobility here, probably the best mobility he'll have on any stage. But, even though he has great mobility, there is a large chance that you'll get gimped here. The obvious reason is that there are no ledges, but this works both ways.
In my opinion, you should CP this stage against characters that have HORRIBLE aerial game, such as DK, DDD, Bowser, and ESPECIALLY Olimar. DK has strong aerials, but will be EXTREMELY easy to gimp since his recovery can be Mirror Shielded. Since the main platform has no ledges, it will be extremely easy to gimp him with a Mirror Shield gimp; same goes for Bowser. DDD isn't as easy to gimp, but you 'll be able to punish the landing lag of his Up B, which will make the player think twice of using his Up B. DDD will most likely stick to just his regular jumps, so if you ever get him offstage, just spam Arrows. And this stage will be absolute Death for Olimar. Since he'll only be able to rely on his two jumps (and the little boost he gets from his Up B) to recover, it'll be especially easy to gimp him. Just push him far away from the main platform and Checkmate. Also, the cars will most likely hit his Pikmin, even if he does dodge them himself. It also helps that it eliminates any Tether recoveries, making Tink and Link especially easy to Mirror gimp.
Although, try not to take characters that have a strong Dair spike, such as Falco, or Kirby, since they'll be able to Dair spike you right onto the runway and potentially get you road killed. Obviously, try not to take another Pit on this stage either. Also, taking MK here is a good way to get rid of any kind of planking shenanigans, as people said. It'll also make sure that the MK will always land on the stage whenever he uses a Tornado. It also might make it easier to Mirror Shield gimp him on this stage, since there are no ledges to save him.
Basically, take any characters who are horrible in the Air to this stage, as well as characters who rely heavily on ledges for recoveries. Try not to take characters that have Dair spikes (or any kind of Spike), or characters that do well in the air to this stage. As long as you do that, you should be fine, character wise.
Also, look for any Footstool road kills. They're lulzy XD.
EDIT: Oh, and to answer your last question, Dskank; it's the greatest stage of all time because of Road Kills :D.