Demand does not go one way. French terry, with its looped back, is preferred for year-round wear, lighter hoodies and a clean look, while 3-thread fleece with a brushed back remains the choice for the cold season. French terry washes easily, drapes well and takes clean print. Fleece insulates better but pills faster if the quality is poor. There is no universal winner: choose by season, market and target price, and keep both in a balanced range.
Rising demand for french terry or fleece: which sells better?

french terryfleecetrend
The right fabric for each garmentWhat fabric do I choose for knitted dresses?
For knitted dresses choose single jersey of 160–220 GSM with elastane, or interlock of 200–260 GSM if you want a firmer drape and a more elegant look.
The right fabric for each garmentWhat material do you pick for women's knit tops and blouses?
For women's tops choose a fine combed single jersey of 130–180 GSM, often with 3–5% elastane for shape retention.
The right fabric for each garmentHow do I choose rib for the cuffs and hem of hoodies?
For cuffs and hem choose a 1x1 or 2x2 rib with a weight close to the main fabric, usually 280–380 GSM for hoodies.