Brushing on one side only, usually the inside, is the standard for hoodies and fleece: the outside stays smooth and printable while the inside becomes warm. Brushing on both sides gives a very fluffy, blanket-like fabric that is less suitable for printing and has a more casual look. With both sides raised, pilling appears more easily and cutting needs more care because of lint. Choose by product: hoodies and tracksuits are almost always brushed inside with a smooth outside.
Brushed on one side or both: what is the difference?

brushingfleeceone-side
Printing & decorationWhy does an all-over print look crooked on knit fabric (skew)?
Circular knit tends to twist, and the tube can lean so that wale lines are no longer perpendicular to the fabric length.
The right fabric for each garmentWhat GSM and knit should I choose for an everyday basic t-shirt?
For an everyday basic tee choose a cotton single jersey of 150–180 GSM, ideally combed or semi-combed yarn.
The right fabric for each garmentWhich fabric suits promotional t-shirts with a logo?
For promotional tees choose a cotton single jersey of 140–160 GSM with a smooth surface and even colour, because high volumes and tight budgets call for a sound…