No, the presidio is NOT an automatic unless you specifically buy the automatic model, which is a lot more than 2x the price of a mini-grip so I doubt that's what we are looking at here.
To the OP, which mini-grip and which mini-presidio are you comparing? The 525 has aluminum scales and a flat-ground 154CM blade vs the 527's hollow-ground 440C blade. For the mini-grips, 556 is saber-ground and the newer 555's are hollow ground with a thumb-hole, and then there are all the different blade profiles for each set...
In any case, the greater differences for me are blade shape (I prefer the presidio drop-point) and handle-length: mini-presido is 4.15" vs. mini-grip is only 3.87". That 0.28" combined with spine-to-belly width spells the difference for me between a tiny knife and a small knife. The mini-grip does not fit my hand, it is too small and I can barely hang onto it vs. the mini-presidio and mini-barrage which fit fine. The mini-grip is a tiny beater knife (blue class) vs. the finer quality of the mini-presidio (black class). Whether you want to pay extra for the higher quality is up to you. I'd advise taking both in hand somewhere (e.g. REI) and getting a feel for which you prefer before deciding strictly on cost/value.
Btw, why are you focusing on two mini-knives rather than regular sized knives more comparable to the others you mentioned?