I've had the Alpine Start for all of 4 days and ~13 hours of use, and due to weather haven't used it in temps above 5F. That said, it seems promising. Spitballing a recollection from last year (when I had a Rab Alpine), I'd say breathability is a bit less, and wind resistance is a bit more. If you create an arbitrary scale of air permeability with a Boreas at 10 and a Houdini/Cirrus at 1, the Alpine would be 6.5 and the Alpine Start 4.
DWR seems really good. There's normal good DWR, which from the factory will bounce water off just fine, and then there's Epic DWR (like the Wild Things Tactical wind pants of which I'm very fond), where said water seems to actively bounce off. The Alpine Start is very Epic like. Again, what really matters is how long this lasts.
To further the mini-review of the Alpine Start:
The cut is very slim and athletic. No tail drop. Underarm gusseting is fantastic, the hem does not move biking or skiing. Arms are just long enough. Wrist elastic could be a bit tighter to seal over gloves. Hood is big, definitely an over helmet fit. It does have elastane in the fabric, but dry rate and moisture uptake seems to be right up there with fabrics like Quantum and Microlight. Did my best to snag the fabric during a protracted bushwack exit skiing yesterday, and had no success.
This last is the issue I had with the Alpine. The soft fabric seemed prone to snag on brush. I have high standards in this area. For most people it is probably not a concern at all.