First off, I have to say that SubGravity has spectacular customer service and really listens to their customers. They are constantly striving to improve their products. I recently got a firmware update for my SG-1 electronics on my Defender for example. I have always (and still am) been a cheerleader for Shearwater and I must say that SubGravity is in the same league as them.
I am still pretty new to my Defender but it is working exactly as it should and I am finally getting more comfortable with the new rig. There are subtle differences that I am getting used to. Some are what I think are improvements and some I am not sure about yet. The only negative thing (if you can call it that) that I have come up with is that the primary is not a Shearwater, but that is only because I am so used to SW and thus my biggest learning curve. The rest of the unit is extremely well built and solid. The machine tolerances are precise and the fits are perfect.
I may as well plug Jon and Lauren Keiren too. They did my training and did a stellar job. Not only did they teach me the unit itself, but they also managed to instill some long forgot basic refreshers and some new aspects of diving at the the same time. Probably some of the most comprehensive training that I have ever taken. They even managed to make it fun and enjoyable for me to look like a complete idiot as I learned the skills and drills.