With push/push, you just push each time you want to switch position. I find it is easier and faster than grabbing and pulling when you want to activate. Moreover, it is easy to push to buttons at the same time... It is harder when you need to pull them.
Some people prefere push/pull because when pushing or pulling, they are sure to get the position they want (while with push/push, since you switch position, if you are mistaking the initial condition, you will go to the wrong position). However, you usually actually know yet in which position you are, and you can still have a look.
It is a matter of choice, but push/push are faster, you do not care about slippery knobs, and you will never tear the knob away while just trying to split coils.
By the way, I got Tim's answer: the 4-way toggle from BKP are the "good ones". So you can take one without hesitation, to put HB in series or invert phase. (Plus: at this point, two additional wires for the 4-way toggle will not change a lot, even if it is your first wiring. ^^)
By the time you get your order at home, I will have done the different wiring diagram. So no need to choose now what you will do with your material. ;)
