Hmm. Well, KevKev. Look at it like this. The vertical distance you lose isn't that bad and you should never do it when you don't have a double jump. However, it is good for stalling. Say someone's on the edge, waiting to edge hog. You do PTP and they are most likely going to get up, this might give you enough time to get back on.
Basically, KevKev. Unless you can do (pardon the pun) perfect, I wouldn't recommend using it. You'll just lose height. As for how much horizontal distance it gives you... I don't know. Ask Smashmac, as he is master of all things Doc.
EDIT: What the heck does IIRC mean? I keep saying that, and I feel like it is a meaningless abbreviation I'm going to end up hating.