Automatics have some problems. With vacuum switches for a new vaper they can clog up and the switch gets ruined. With sound activation they are occasionally set off by loud noises. (reports of anything from loud country music to a semi truck nearby)
Because of the flooding problem I don't recommend them for new vapers.
The positive side of autobatts is that they allow you to go hands-free if you wish, and you simply have to inhale to activate them.
Manuals don't have all the same problems, and generally give you more control. They don't get flooded and clog. They CAN go off if you keep them in your pocket and something ends up pressing the button. At worst, this just means the atty may pop. They don't get hot enough externally to do any serious damage before you notice the heat, and again, the sound activated autos have the same problem with a different cause.
I recommend these for new vapers.
The good thing about manuals is that they allow you to pre-heat the atomizer before taking a hit. Shorter more consistent drags.
Edit:Just realized you're a veteran...guess it all still applies. ^_^