Sharkbites actually work better with PEX than with copper. Especially near a shower or other closed areas prone to getting condensation on the pipe. The little stainless teeth bite nicely into PEX and the OD of PEX stays smooth against the O ring and can't abrade it. Moist air near a sharkbite on copper puts two dissililar metals in a weak electrolyte- the stainless and copper battery causing copper oxide buildup that can eventually ruin the O ring seal against the pipe or erode the copper until there is nothing solid to bite and the assembly leaks.