Originally posted by biz-engineer although when it's being turned into arguments made up to prove that different format do the same, I also reply with the same stupid arguments. Nicolas and Normhead have decided for themselves that they aren't going to get a Pentax K1, and they are basically saying (I simplify here), if you consider equivalence, crop and 24x36 are doing the same, and so I disagree with that.
This is not the case, I said many time here that FF provide better quality and that I am all for people going FF if that's their thing.
My point is to consider the benefits you get from getting it and the drawbacks.
Benefit are higher resolution, more room to arbitrate between noise and dof and market segmentation that tend to keep the most high end features to FF bodies (like top end AF or 50 iso sensor)
For Pentax FF only, the price of the FF is quite interresting and there unique feature like SR, the bundled astro tracer and pixel shilft. Handling is nice with a fully articulated back screen and lot of control thanks to the 3 wheels mechanism.
Drawback are the price of the body, associated with the price of high end lenses. There the size and weight with K1 being one of the heaviest FF bodies out there. Lenses are typically bigger for the same reach.
For Pentax FF and Pentax only, the lens offering is lacking choice. there no FF prime bellow 31mm, no f/4 zooms (like 24-105 f/4, 70-200 f/4, 100-300 f/4), no entry level tele (70-300) and super tele (150-600). There a lack of portrait primes choice (85mm & 135mm) with only the FA77 covering it and ovrerall there few f/1.4 primes. Many of the lenses are still using SDM or screw drive meaning you are not going to fully leverage that ultra fast AF performance for your action shoots you could expect if you were on Canikon.
You have to know your priorities before making a choice. If you do weddings all day and shoot in very demanding conditions all the time, FF give you an edge. If you care about size, weight or money, a carefull choice of an APSC setup or, why a m4/3 could be a better fit.
And yes, in most cases, it may not matter that much anyway. If you slightly missed your focus, if you didn't frame the picture well , if you didn't manage to be there when the light is best or to capture the right instant, you'll get quite average shoot, even with the best body in the world. It might be more important to train, be at the right place at the right moment than spending time to get the best gear. For most it is easier to get better gear than to become better through... On is just money, the other require time, dedication and a bit of talent.