In a nutshell, from this rookie's understanding...
Use Vltor A5 unless any of these three conditions apply:
- You are forbidden by employing-agency policy from replacing buffer tube, or are building a strict cosmetic-clone of a milspec config
- You can't afford the extra 3/4" length of the A5 tube, like a short arm or a minimum-size pistol, or a Michigan-style length-limit on pistols
- You're on a tight budget and need the extra forty or fifty bucks somewhere else
If any of these apply, use Geissele instead.
How's that for a nutshell, Tom and Buford?