For my part, there is a few months, I replaced the original hard drive with a SSD, I now have a very powerful machine, ultra responsive and that will last me a few years! A good investment;)
As for storage, I have kept the original 500GB hard drive and installed instead of DVD drive that no longer served me (thanks to a "Data Doubler").
Unlike the MacBook Air or MacBook Pro Retina, choosing the Macbook Pro, you have the ability to scale your machine! Where you will have Ram welded to the Macbook Air, for example ...
I had to change the layer of the hard disk there is little time, it is defective and causing the Kernel Panic several times a day, but again, with the extensive use I make of ... it's like a car, over time, change parts!
To conclude: this MacBook Pro is a good investment, even if you're not ready to reach into your computer, it is a reliable machine that can easily evolve!