I've been wearing this vest almost every ride. I'm the early bird type of rider who wakes up at 5am and by 7-8am, I usually finish my ride. I wear the vest simply to protect my chest from cool wind in the summer morning, especially when I ride downhill. And because the back is a mesh, it lets my back cool when I climb. The material is very thin and light, almost like you don't feel that you are wearing it. It also has a large enough pocket to stow my snacks, my galaxy S3 phone, and a small towel to wipe my nose. Overall it's a perfect vest for me.I find that Pearl Izumi stuff tends to run a little small, so I got the XL. It is big, but I wanted it to be able to fit over a couple of layers and I have had problems with PI Stuff being too tight in the bust before. For reference, I am 5'4" 140ish, 32FF. I would definitely recommend sizing up if you are on the fence about it. The material is great - lightweight and will fit perfectly in my jersey pocket. The orange is very bright and should be easy to see - perfect for riding or adding visibility when walking the dogs.I typically wear a medium or large in tops, and after reading reviews, I ordered an extra large. It was too tight. I can just barely zip it over my chest, but there is no hope of running in it because I can hardly move to breathe. This is a very light weight vest and I do not anticipate that it will keep any wind or cold out. On the plus side, you could wear it (assuming it fits) in slightly warmer weather for visibility. I ordered the Safety Orange and it is a great color for high visibility. Also, there is a pocket on the back that would be a great place to clip my flashing lights and store some energy gels. Sadly though, I can't wear because these run tiny.I bought this to for a family member to ride on cool mornings. The is perfect for days in the Mid 60s and low 70s or under a outer jacket. The front keeps out the wind while the vented back allows you to stay cool while hammering up hills. Great fit and high quality materials and construction. Back is the perfect length for riding on the drops without exposing your lower back to the elements. Back pocket is large enough for your tube or gels. Vest folds up very small and can be kept in your jersey has the day warms. If you need something to start your rides or finish cool days this is the perfect vest.This is what I was looking for- very bright for running on the streets. It's very light weight, which is as advertised, but I had hoped it might be a little more substantial. I like the back pocket for carrying a gel or my iphone. All in all, I am very happy with it. It fits well, even over a long sleeved shirt.I love the idea of this vest, but just reordered it in a size xl. I am 5'6: and under 150 lbs. I usually wear a 12/14 and large is always big enough, sometimes too large. But I could not comfortably zip this. It is vented in back which I like. The pink is awesome...will be great for biking once I get one that fits!I'm returning in part b/c this item arrived several days too late...aside from that, the vest was just OK to me. No pockets! How did I miss that in the description. As other reviewers noted, it does run small, so order one size up, especially if you're busty. I did heed this advice, which is why I say it fits as expected. I'm keeping the Suogi (sp) convertible jacket/vest with magnets. It's so easy and has pockets....This jacket looks fantastic on. I'm 5'4" and it hits me about the same place as the model shown (I got the medium). It's narrow but not tight. It's very comfortable - I barely notice it. The red really is a true red - basic, perfect, red (no orange, no purple noted). It should be great for wind (especially once sweaty) but I don't expect it to add warmth (which is desired), given its mesh back. I also purchased the jacket in peacock and it's similar but with sleeves and the back is solid, rather than mesh. Both PI products look great.Kuschlig warm und doch ganz leicht! Tolle Farbe, fällt auf, sieht aber nicht wie eine Warnweste aus. Schönes Material, gute Verarbeitung. Reißer ein wenig zierlich, muss man vorsichtig sein. Klasse Teil, pearl Izumi halt. Trage normal Gr. 42, Brustumfang 101 cm. XXL war viel zu groß, L war einen Tick zu klein und XL passte super. Der Umtausch funktionierte einwandfrei, Danke an den Händler für die Geduld.Schmal geschnittene Weste - Farbe allerdings nicht wie abgebildet sondern in smaragd grün. Feines,dünnes Material, hoffe mal dass es auch etwas winddicht ist. Weste fällt Größen mäßig aus. Netzteil im Rücken und große geräumige Reissverschlusstasche im Rücken. Gut verarbeitet.