I was initially a bit concerned due to the confusion some folks have had setting up and using the system, but after crash testing a hit air vest in a high side in one of my races I was sold on airbag technology. So, I decided to get the missile suit and race airbag system.
Right out of the box the instruction manual seems intimidating but really it's just that it is in multiple languages. Instructions are actually really easy to understand. On top of that there are only 2 available plugs on the airbag vest and the charger fits into one and the suit fits into the other so it is very intuitive. Activating the vest is very easy as well, just close the Velcro clasps on the vest and then the lights do a little light show to show you all the lights are working, then it flashes a light to indicate remaining charge, then it goes green+yellow to indicate standby mode. From there it will wait until it senses you are on track and riding then it will automatically arm. There is no time limit to standby mode. You can put your suit on and activate the system 30 min before you go on track and it will stay in stand by and wait for you. Also, it will automatically cycle active and standby so say you have to stop for a red flag then go back out you won't have to reactivate the suit or anything. As far as getting a hold of a-star and registering the suit it is really easy. The instruction manual gives you the website to go to and if you just call the customer service number they send you right over to the person you need to talk to, I didn't find anything difficult to find.
Airbag didn't effect suit sizing for me, it does take up some space though so it possibly could if you are already maxing out the suit in the shoulder/chest/back area so for sure try the suit with the airbag before ripping off the tags. Also the airbag will make the suit hotter as it will impede some airflow. All in all very happy so far but the real question is how it works in a crash which I hope to not find out anytime soon!