I have an 05 Proto Matrix and an 03 shocker. My A5 was OK, I didn't like how the cyclone feed stuck out the side and stopped working every other day of paintballing, so I got rid of it.
Also, longer barrels aren't necessarily better. anything over 16" is pointless and will only make your gun harder to move around. The only reason people go with 16" is so they can push bunkers in to get a lower profile.