This is not going to be an anticlerical one although this a critique of an almost sacred and unquestioned positioning technique.
Here is a brief summary why positioning crosses are stupid.
First of all: what's good about them? Everybody understands them quite instantly if the axes make sense.
What's bad then? Same answer: Everybody "understands" because the axes make sense. So you try to make them make sense, don't you. Junior Planners keep coming and offer solutions and you go "no, give this one another name", "what about this brand here, it doesn't fit the logic", etc. So basically you do not think about reality any longer. You just try to make the axes fit the brand logos somehow. You make things up. That's alright if everyone is aware of its fictional character but noone ever is.
It's important to understand four things about such crosses.
1) The world is not two-dimensional; a powerpoint slide is.
2) It might very much be the case that the particular slice-of-world you are looking at is not dimensional at all! This means that positioning might not be about finding a space on a continuum or being "somewhere between A and B". Simply because there is no "space" with a coordinate system similar to the physical space we live in. An example might help here: Seeing your DYI market as a place with widest product range & best advice (OBI) is simply a different kind of thing than seeing it as a transformational offer for personal development (Hornbach). There simply IS NO continuum between them to slide along, and if you make one up it will not help much. Just like there is not much land to build your house on between Ireland and Iceland. (I hope this is geographically right.)
3) The axes are derived from the objects / brands analysed. So they vary depending on which brands you throw in. This is even more striking if you have crosses derived by quantitative methods (MDS, Factor Analysis etc.) They simply vary with every brand you add or take away. But what the picture of the cross suggests to the viewer is something different: it says "there is a space prior to the objects located in it". That's just the metaphor of "space" working in our brains: Space must be prior to and independent of objects. Well, that is exactly the way a positioning cross is not be read!
4) By using such a cross you just build a box you then try to think outside of.
So beware of positioning crosses when you see them! Be much more sceptical if market researches present them ... as valid representations of reality, of course.
We actually don't need a space between brands. Just care about the chunks/clusters more than about the dimensions inbetween. Al Ries just picked a wrong word. What he meant is "owning a concept in people's heads". By calling it "positioning" he evoked the space metaphor which does not help much.