This is now my second year of owning this jacket. I purchased this jacket at a cut price for £110, i think? it's been a long time.
I do agree with some of the views rasied buy others, noticeably the thinner event shell. Yes it may be thinner and not as warm as others, but in all my years as being a cyclist, hiker and general active out door person all year round, i have never found an item as breathable as this jacket. I do not pretend to be a mountaineer, i do though, spend a lot of time in the out doors and have done all my life no matter what the weather. I cannot comment on the helmet compatibility as i have never used it with one, other than a fleece beanie or over the infinity which it does just!(massive loft on these) . I do like the lumbar draw cord and storm flap which really does help keep the rain and biting wind at bay. The event fabric does take a bit more looking after with regular washes than say gore-tex, but two years on and being caught in some seriously appalling weather this jacket has never let me down, and at the end of the day that is what you want! Cant recommend it highly enough.
One thing i would say is the sizing, i am a medium with long arms and a long body, but even this came up a little large in the med size. However this does allow me to layer up with fleeces and gillet, or just have my infinity jacket on underneath.