I think why some people have issues with saddle valves is probably because some are hardened tips some not I believe (or maybe some are hardened better than others with better metal). A good hardened one would probably last a lot longer. I'm sure they sell really inexpensive ones because they are probably only used once most of the time.
I would pull the tubes off and use my Dremel style rotary tool to make hole, wash the tube and put it back on if I wanted holes in poly-filled cartos. I use CE2's so I slot them instead by pulling the tubes off, slotting, washing and then putting them back on. It's pretty easy with a little practice and when I need to replace the insides I use the already slotted tubes again usually...