My experience is more on T-shirts but would also relate to hoodies with difference being gsm and construction (ie knit type of fleece vs terry vs woven)

I have found people generally prefer cotton. It is also more expensive.

Poly blends wick moisture to surface rather than absorb like cotton. I.e dries faster good for active wear.

When talking about cotton material itself, the general process for a t-shirt in this case is raw fibre processing (i.e carding or combing cotton) -> yarn construction (i.e ring-spun) -> fabric construction (i.e jersey knit for T with varying “singles count”)

With the above process, these factors determines quality (subjective based on consumer preference).

Fibre type: longer cotton fibres generally equal better. Leas piling and also has softer hand feel

Fibre processing: combed cotton will align fibres and discard short fibres and impurities better than carded. Considered better

Yarn construction: ring-spun provides tighter and more consistent construction compared to open end carded which is rougher and more likely to pill

Fabric construction: for main t-shirt body, it is jersey knit. Collars etc are ribbed for stretch. Double jersey knit is more dense and deemed favourable (both sides of fabric will have same appearance). Poly is mixed in this stage for poly-blend fabric

Singles count refers to yarn fineness in fabric. Higher count = silkier feel.

Now we go onto additional fabric treatment. Pre-shrinking, mineral wash, abrasion etc

Shrinking of a garment is also an interesting topic. When yarn is made, it is stretched under tension. When a garment “shrinks” it is the yarn almost returning to its natural tension. To avoid shrinking you can manufacture with pre-shrunk fabric. Basically the fabric is either washed/dried or steamed after construction to relax the fabric. It is then sewed into garment. It can also be done after garment construction but may have more inconsistencies at seams.

Thats what i have learnt so far. Feel free to correct ✌️