What size hands free system do you plan on getting? If it is more than 1 liter than I say:
Wow, that's a lot of water. Where do you generally hike? Assuming you get the 2L hoser or big zip, are you ever going to have a reason to carry 4 liters of water at once?
If it is a 1 liter and you have a need for 3 liters of water at once, than I say get a 2l hands free and 1 liter bottle.
Myself,
I carry two 900ml evernew bottles so that I can have one clean and one getting clean (I dropped a tab in it) at all times. I make sure to cross water often enough for this to work. If I bring my platy 2L I only have one 900ml for a total of 3 liters of water. This is for trips where water is more scarce.
As for getting the Hoser or Bigzip, that depends on preference. The big zip is easier to fill from some water sources, but that comes at the penalty of a few ounces. I personally don't have trouble filling my bottles so I would get a Hoser.