What are those very good features of which we speak? First, the Jersey has a full-length zip, and you can't beat that for maximum air circulation on hot, sweaty climbs.
The zip in question feels like one that's going to last the distance rather than one of those that's going to fall apart at the slightest provocation, and it locks firmly in place wherever you want it. A fold of fabric at the top of the zip means it can't irritate your neck.