Square pots or round?

Which do you prefer - square pots or round ones?
I have too many of both and need to dispose of some - but which ones?

Your choice with reasons to help me decide, please. 

Logically you would think that square pots would utilise a given space better. But how many squares are there in nature?

I dunno, I'm probably just trying to justify my like of round pots as opposed to square, so in my view, ditch the squares!

I don’t really understand the I’ve got to many pots part of the question  
As to which I use, tricky. 
I use more round pots only because that’s what I have most of and more sizes. The square ones I have are stacked very neatly in the corner of the shed so more difficult to get to as all the round ones take up the rest of the space.

           

I'm trying to sort out GH No 3 and turn it into a better sowing/potting up place but all the pots that have been dumped under the staging have fallen over.  Seemed like a good time to sort them into sizes. However, if I get rid of some, it would be less of a problem.
Please don't think that these are all I have - there are boxes of pots in the shed and a jumble of them in the log store that have probably turned into homes for beasties.

I try and use the square ones. They fit better into water trays etc than the round ones and with my wobbly legs are less likely to fall over in transit.

Square ones - always use those first as they fit together better on trays or holders, and they stack better when not in use.

I prefer square. I use what I have to hand mostly. I've oodles of sq 3" pots courtesy of dear deceased mama, I would like bigger square ones but make do with round because I'm too tight to buy more and too hoarderish to throw any away.

Square hear too

I prefer square ones but I seem to have more round ones mostly because I picked up lots from the Charity shop for a couple of pounds, I figure square one must be keepers seeing as I've never seem them for sale in charity shops..

Thanks everyone.
A definite preference for square pots and I have to admit - they're my choice too - mainly because they fit better in a tray.
I've read that round ones use less compost than square, as there are no corners to fill. Not tried measuring them this way so don't know for sure.

Sorting these pots is very frustrating - such miniscule differences between pots that look identical at first sight. A fraction taller, or wider, a different rim, various drainage hole patterns, some with holes up the sides as well as the base. Not to mention the flimsiness or rigidity, ridged or smooth and the colour.

My first sorting rule was that any single pots would go, as well as any that were damaged or had teeth marks (dogs not mine). I've only finished the square ones so far and there were only about 10 odd pots. Not making much of in inroad into my pot clutter. This could be a long job.