I don't have a problem with pulling nails out of the planks. That is easy enough for me to turn the board over on the underside and pound the nail down, and then use a hammer to pull the nail out from the top of the board.
It's the nails in the 2X4's that are much harder to remove, and especially if the nail head pops off. That's when I bring out the nippers or Crescent Code Red pliers. Because I have been using the 2X4 stretchers for my planter and raised bed builds, I am taking the time to remove the nails out of those boards.
Yes, I'm a big fan of using the Sawzall method to quickly cut those nails and remove the entire plank off the pallet. Works great on many pallets. Sometimes I need a full length plank, and the Sawzall method is about the best in keeping the whole board useable.
It's easy enough to use a punch to pop out the nail heads from the planks after you use the Sawzall to cut the nails. But, the nail bottoms in the 2X4's are about impossible to remove. Not a big deal unless you plan on using the 2X4's and need to cut them with a saw. Those imbedded nail bottoms can destroy a saw blade.
If I use the Sawzall method to break down the pallet, I set aside the 2X4's for projects that will use the entire length of the board without cutting it. That way I do not have to worry about cutting through a nail and ruing an expensive saw blade. That is why my raised bed planters are 4X4 feet - taking advantage of the entire 2X4 stretcher and I don't have to remove the nail bottoms if I don't cut the board.
If you only want the planks, and can live with shorter pieces ~18 inches, then using a circular saw or a jig saw to cut the wood alongside the 2X4 stretcher is a really fast way to break down a pallet and you don't have any nails to pull out or punch out at all - assuming you don't plan on using the 2X4 stretchers with the ends of the planks still attached.
All my planters and raised beds, so far, just use planks cut down to 16 inches, or less. So, the circular saw method works great for me to quickly build up lots of short pieces to use.
I have learned that some pallets are built in such a way that one breakdown method might work better than another on that particular pallet. So, it's really good to know a variety of pallet breakdown methods to take better advantage of what the pallet offers.