Just wore them once and I love them already.
They kept my arms warm at 50F ride this morning without overheating.
I ordered a size medium and they fit perfect. No slipping at all and comfortably snug.
The length was long with no gaps, perhaps a little extra long which is great.
My arm measurements are:
Arm Inseam: 16"
Bicept: 11" (unflexed)