The Bionic uses the Climateblok fabric which is heavier and is better at shedding nastier weather and shrugging of cold winds. It is a better jacket for lower activity levels in cool temps or more activity in colder temps. The Pnuematic, with Apex Aerobic, breathes better and is the better jacket for more intense activity levels in cool to cold temperatures. It would not be as good on its own at keeping you warm in cold, windy weather since the fabric is light and made to be a little more wind permeable. Hope that helps!

The two jackets are also made of different materials. The Pneumatic is made of Apex Aerobic which is a very light weight and breathable softshell. It's air permeable so it will be wind resistant. The Apex Bionic is made of Apex ClimateBlock. It's a much heavier softshell material that is rated to 0 CFM for air permeability. This means it is essentially windproof.

bionic has no lining, just brushed fleece...the difference is that this is kind of a stretchy, lightweight, aerobic jacket that does not offer much protection form the elements. the Apex bionic is a Fully windproof and nearly waterproof outer shell...the Pneumatic is lighter and more breathable, Bionic is warmer and more protective

the bionic has a fleece lining on the inside and is designed for colder weather. See the same Q&A below.