Fleece insulation has been a staple for backpacking and other outdoor pursuits since Patagonia introduced synthetic pile and then Synchilla fleece decades ago.
Over the past few years I have seen more and more articles comparing fleece to synthetic polyester batting material such as Polarguard, Climashield and similar materials as a better option to fleece.
These batten materials are lighter than fleece with an equal insulation rating, are more compact when packed, and the manufacturers state the material insulates when wet.
Sounds like a winner to me!
Or is it just hype?