This is a comfortable jersey it moves well with the body and the temperature on the first ride wearing this jersey was 90F and I didn't need to unzip for ventilation.
The one flaw preventing five stars is the stitching between the upper and lower fabrics above the pockets. After the first ride I found the stitch had failed and opened a 1" long hole at the seam. I probably just got a bad one, would love a replacement but have been too busy to pursue.
Regarding the fit of the Giara jersey, it is slightly relaxed. I am 5'6", 125 lb., and I own this jersey in a medium and a small. The medium is very relaxed on me. I would call it "club fit". The small is a much closer fit, no fabric flapping in the wind, but the fit is not at all tight or restrictive. The fabric on this jersey feels good, works very well in Florida's hot and humid summer weather, and over the course of a full season the mediums have held up very well. The small jerseys are fairly new, but I expect similar durability over time.
I do agree with the other review that the description on size is misleading. However I tried a small and and medium. I'm 145lbs with muscles and the fabric on the should and chest stretches comfortably. I ended up getting the small as the medium bunched up too much on when in cycling position. The Jersey is very comfortable and the side zipped pocket is excellent. The side material does a great job venting. Note that for their other jerseys you will need to size up one like the description says just not this one.
Description says:
Relaxed cut offers roominess for pedaling upright
Performance fit: Sportful apparel is designed with a performance cut that often runs smaller than that of other manufacturers. Consider sizing-up one size to ensure a comfortable fit � e.g., if you typically wear a Medium, select a Large in Sportful.
Not sure which to believe. Which is it?