Merino sock monkey (Left) meeting Alpaca/Merino sock monkey (Right).
Which one you like more?
Depends on the quality of the fibers, Alpaca & Merino are relatively soft fleece among others.
Alpaca = 18 to 25 micron in diameter
Merino = 12-24 micron in diameter
Thus, Alpaca fleece, similar to Merino Wool, does not have the "scratchy" feeling.
"Any wool finer than 25 microns can be used for garments,
while coarser grades are used for outerwear or rugs.
The finer the wool, the softer it is,
while coarser grades are more durable and less prone to pilling."