I own a PullPal. I've used it quite a few times, mostly for training demonstrations but now and then for actual recovery. My success rate with it runs about 50 percent. The sand needs to be deep for it to bury properly; if it hits rocky substrate it will turn on its side and unbury itself. For the bulk and weight it's just not attractive to me as a regularly carried tool. I'd much rather rely on a shovel and Maxtrax—which have, never, ever failed in any kind of sand for me.
Of course, the first thing I do when bogged in sand is air down. If I've already aired down, which is always, I air down again. If that doesn't work . . . air down some more. 14psi didn't work? Try 12, or 10, or 8. If you've been smart and got off the throttle as soon as you realized you weren't moving any more, you'll probably drive right out.