Regardless of the particulars, I find the most important thing for readability is for the author to have made some kind of decision and stuck to it. The most illegible style is no style at all.
There are the exceptions of very widely used projects where contributors will only look at the code a couple times when making a change to be pushed upstream or where there are significantly junior developers that need a narrow scope of the language to help them with the learning curve and getting up to speed with the code base.
In my experience(which is very anecdotal I admit), the requirement for consistency is more about a particular personality trait that many developers have - the need for order and control - as opposed to a requirement for quality production code.