complete disaster. terrible for your skin, feels gross, falls apart, and cannot be repaired. meanwhile my cotton pants that have been repaired many times are still treasured wardrobe items almost 10 years on.
Other than that, good moisture and odor control, comfort/mobility of stretch too much of life upgrade. Also fairly wrinkle/iron free. I'd take convenience over durability anytime.
I will say synthetics haven't been able to replace bed sheets on most of criterias above.