It comes down to nomenclature. The paintball world seems to have locked onto a poppet valve being a separate mechanism to release air, and a spool valve means it is built into the bolt. In the rest of the world (ie. pneumatic/hydraulic industry) this is not the case. Poppet=face seal and spool=axial seals. I guess any more arguing won't really make a difference, I'm just stating my opinion, take it or leave it.
For more clarification,
Read xluben's posts on this thread. He explains why there's so much confusion and why it's technically spool...
Seeing a lot of questions and comments on how the Etha works. This post is in my Etha thread, but it seems like people are missing it, so I figured I'd make a separate post:
Below I have animated the images from the manual. A few of my comments on the operation...
This is a spool valve.
It is not based on the GEO drivetrain.
It is not a poppet valve.*
*All of the seals are axially sealing o-rings. There are no face seals (or "poppets"). The manual chooses to call the center stalk a poppet, but it is not actually creating a face seal.
Two key features of this design are the fact that it seals the dump chamber when the firing sequence is initiated, and it that it has a 2 stage bolt speed profile (starts moving slowly and then rapidly speeds up on the second half of its movement). The first is important because sealing the firing chamber is critical for efficiency. The second will allow the gun to deal with misloaded or jammed paint very well.
Enough comments. Here is the animation:
Edit: Found a better animation online. No idea who made it
Edit 2: Even better animation from lentyay. Thanks!
Here's a quick rundown of the operation (taken from the manual).