I actually started out collecting just the minis. The big 75ml EdTs were just not around, so I was content to build the full collection gradually and experience them in minis.
Then I hit the jackpot and found 5 used bottles on Ebay and bought those immediately. That left me with another 7 to source. I found 5 more full bottles, including a 'find of a lifetime' Vacances pure parfum and the hard to find Colony.
That left me two more, which I have not found yet - Amour Amour and Moment Supreme. I have both of these in PdC and in the case of MS, parfum. Naturally I prefer the PdC concentration to the EdT which is very light and somewhat fleeting.
So, that really made my mini collection redundant from a usage point of view. So that's why I say these are now more an investment. I never expected to find Colony or Vacances in mini and found the last pieces to the jigsaw in Italy, of all places.
Naturally being in Australia, exchange rates and freight tend to add quite a bit to the overall cost of things, so I generally have to pay far more for my things than you lucky lot in the US.