I have a few decades of mountaineering behind me and many more decades of backpacking, camping and hiking. I have been there when new things like Gore-Tex, polarfleece, polypro and other miracle fabrics came along. While some have been excellent when used properly and understanding what to expect, others are hyped too much and really seem to perform somewhat less than desired. While I have numerous polarfleece items and like some aspects of them, I also have become aware of limitations and some negative aspects. Besides the melting to skin in a bombing (which I no longer need to endure...I hope) the fleece will melt small holes when a campfire ash lands on them and have some potential to burn of not watched carefully. I also do not like wearing fleece while hiking or doing strenuous activities, it makes me sweat and feel uncomfortable. Wind cuts through most fleece garments and can make me feel colder than if I wasn't wearing it.
Synthetics do dry rapidly because the fibers do not soak up water, only retain it between actual fibers, which is a good feature. It does not seem to keep me very warm if it becomes wet though, which is not a very desireable feature and could be dangerous in extreme conditions.
I have gone back to a combo of wool, synthetics and wind layers of Gore-tex or similar. I prefer the properties of wool mainly the abliity to insulate when completely wet, more wind resistant and does not end up with small burn holes when worn near a fire. Wool also drys rapidly compared to other natural fabrics and most wools are comfortable worn next to the skin. I realize some are allergic or have itching problems with wool, that is sometimes due to the quality of a particular garment.
I recently watched the Everest shows on Discovery and noticed a lot of synthetic clothing, which is not all bad, just probably not a good as a mix of wool in the layering. It is to me, more a trend then a carefully researched method of outdoor dress. I would like to see some serious research into the effects on a person in all conditions while wearing synthetics vs. wool. I think some polarfleece aficionados would be surprised at the outcome! Cheers!