I did a little more digging on this particular jacket, both in its specs and overall reviews. I couldn't find any on this jacket from outlets that I would usually trust. Powder magazine praised it
here generically, which doesn't mean anything. On Helly Hansen's
website, they mention "15,000gm moisture vapor permeability", which without seeing their breathability testing setup, can only be compared to other products in their own lineup. I am slightly skeptical about the membrane HH chose to use as they brought no attention to it. For kicks and giggles, I looked up some breathability ratings and found a nice write-up on
evo.com. For high intensity activities, they recommend jackets in the 20,000g plus range.
In addition, the "52 reviews at Helly Hansen by serious outdoor people" (mjac post 19) seem more like average joes who happen to like the jacket. To play devil's advocate, the jacket features 3 layer construction (it better for $300!), fully taped seams (another expected item for the price), and is (hopefully) decently breathable. It seems like a nice jacket, but this is a cycling specific forum. Some of the most highly praised shell jackets come from
Showers Pass as they feature cycling specific cuts and are exceedingly water resistant and breathable.