I bought it as my third between the three. I use them to layer underneath my ski jacket as well as wknds with jeans.

Volt: Thin enough to wear over a t-shirt and indoors. Works well too underneath the Bionic when it gets colder without having to put on a thick jacket.

Apex Bionic: My personal favorite of the three. It is often my outer layer when active outside and temps are cold but not less than 40 degrees or so.

Apex Pneumatic: I bought it as my "in between" and it fits that job perfectly. Thinner than the Bionic, thicker than the Volt, it has a slight fleece lining. The outside feels like the Bionic but more stretchy like the Volt and a little thicker. The North Face logo is embroidered on like the Bionic (the Volt is not, although after a few washes it looks brand new still). Still thin enough to wear indoors. My only complaint is the zippers (side pockets) bottom out 6 inches up from the bottom of the jacket. On the Volt and the Bionic the zippers reach down 2 inches or so from the bottom of the jacket. This may matter to you if you are looking to use the Pneumatic as an outershell alone or with the Volt underneath. In that case, I'd go with the Bionic.

Lastly, I have an XXL for each and it is close to perfect. Normally in XXL the body is too big and North Face does a pretty good job slimming down the body or chest. I'm 6'5", 235 lbs. Arm length is perfect and I'm a 37/38 in that category.

Used my Apex Bionic Jacket skiing at Snowmass, CO late March/early April '08. Don't let the dates fool you, it was cold and we received 30" that week. The softshell kept me warm and dry under my Spyder winter coat. Later in the week, as it warmed up, I wore the softshell alone up top while skiing and it worked great. Very wind resistant. One note, is that it shouldn't be used as a big time cold weather jacket alone. If the weather is cold (<35-40 degrees), wear it as a layer. Last but not least, I'm 6'5, 235 lbs and the XXL was perfect, including a nice long sleeve length!