DISCLAIMER: I have not yet cycled with this! I use this for snow sports and it's fantastic. I have not cycled with it--yet--but I can see how it may be problematic breathing if exertion intensity increases. As far as breathing on the slopes, there's no problem. I'm the only person in my group of 5 in Austria that didn't get a little chill blane or even frost bite on a -15 F degree day in the Alps. It's effective for warmth and wind protection.
I love this shirt. I'm 6'0", about 180 lbs and purchased an XL because there were no L sizes left. The XL fits wonderfully I originally thought I'd use it as an outer layer while looking for a jacket. I was wearing it on a very chilly day (maybe about 45 F degrees) when a downpour of rain came and I was very comfortable in nothing but this jersey above the waist. I think it looks great, but more importantly it feels great. It has a very soft, inner liner and does a great job against the wind also, though not a windbreaker. I've since found a jacket and frankly, only wear the jacket if this is dirty and not an option. 15+ rides, more happy with it on every ride.
I'm 72 inches tall, about 180 lbs. Purchased a large and it fits very well. Good compression, more comfortable than most bibs I've had in the past. I purchased the yellow and they were true to color also. They stay where I put them which is also a plus, unlike some others I've had. I've been very happy with them and would recommend them. Thanks for selling me another quality product at a good price.