Today, I did update the male hair & beards section and I thought it might be time to write something about the available hair.
There are different ways creators design the hair and every way has its definite pros and cons. To make it clearly, everything usually is mesh, some prim.
Prim hair usually is the old style one, doesnt look detailed but can be made flexi by using flexiprims. The hair is swinging when moving.
Mesh hair gives more details and looks more realistic. It can be resized, moved, rotated. But this doesnt apply to all Mesh. There are different ways mesh can be created.
Unrigged mesh, can be edited to fit your head better. Mostly used for short hairstyles, with longer hairstyles it might happen that it clips with your body.
Rigged mesh means that it is linked with the bones of your avatar skeleton. In this way the hair doesnt clip with your body unless you altered your shape a lot. Its not editable, but most designer have a script inside the hair allowing you to do it.
Fitted mesh actually same as rigged, but being a bit more flexible and adjust itself more to the bones of skeleton when altering your shape to prevent clipping with body.
Full Alpha hair is one of the newer additions. Using this technique, hair can be much more natural looking. But it might cause problems with other alpha parts of your body/face, i.e. hairbase, eyes, eyelashes. Using BOM can prevent this.
What hairstyle fits you and your head, you have to check out by yourself. Best is as usual always try a demo first. Some designers rig/fit their hair to specific heads, usually Lelutka and Catwa.
I hope this helps a bit.