Due to the off-set to one side, the push button stock is o.k. if you are right handed.
But if you are a lefty (not leftist) like me, it's very non-user friendly and annoying. The centered lever stock is much more comfortable and user friendly to me.
Also, the lever stock locks up a lot tighter with the stock extended than the push button.
As mentioned above, be sure to get the correct screws.