As headgear goes, choosing a beret is probably one of the most personal choices you can make. Despite the simplicity of a 'circular shaped piece of felt with a wick', it is amazing how different one beret feels and looks from another. 

Size (yes, size does matter), the density and quality of the wool, the beret's flight, wool or cotton, satin lined or unlined... It's not that simple, really. And that is without looking at the individual buyers personal circumstances: do you live in a warm or cool part of the world, do you need protection from the rain or sun, are you looking for a practical every-day hat that easily fits in your pocket or do you go for elegance and fashion - are you a bricklayer going for 'practical' or an executive wanting to make a statement?

There is a lot to consider...

Flight:

The flight is the fold of the beret, the surplus material that folds sideways. 

On the one end, there are the small diameter berets in 25cm (e.g. the Elósegui Super Lujo 25cm/10") that sit on top of the head without much, if any, overhang; The medium diameter berets from 28cm/11" (e.g. the Boinas Espinosa and the French Laulhères) to 31cm/12" (Boinas Super Lujo's, Tolosa Tupida and Castilla) with a reasonable amount of material "to work with" and, at the other end of the line, are the Txapelas or Plato Grandes, up to 37cm/14.5" - huge berets that offer great protection from any weather, but may require some courage if you (or your environment) is not used to these grand berets.

Generally speaking, the larger flight berets of 30cm and over are best suited for tall people with a large size head (>59), while smaller people with a smaller head size tend to look better (and feel more comfortable) with a diameter of 29cm or less. 

But obviously, no rules exist here.

Material:

Most woolen berets are made of fine Indian pure wool (our South Pacific Range) or merino wool (the Spanish use Australian merino, the Argentinean and Uruguayan berets are made of Argentinean merino wool).

The dense felted wool has a high water resistance and most berets will keep you dry for a good amount of time. A simple guideline: the denser (heavier) the wool of the beret, the longer it will stay water resistant. The Elósegui Super Lujo is the only beret treated with Teflon for waterproofing.

Cotton berets are generally lighter than their woolen equivalent, breath well and are well suited for warmer weather (although many people have converted from wool to cotton berets and wear them year-round!).

The satin lining with the embroidered label is often seen as the finishing touch, pretty, but without any use. Interestingly, you'll find that a lined beret actually keeps you warmer and it also helps to keep the beret's shape better. 

Many French farmers and labourers in the olden days kept their paper money between the actual beret and the lining (after taking a few cm's of the stitching out).