Alright, I've had some time to mess around with the Agis for a little while today and can give my first impressions. Let's get the basics out of the way before we get into the details; The initial fit and finish are fantastic, as to be expected. No sharp edges anywhere on the kydex, the draw is smooth, retention on the pistol and magazine is strong and easily independently adjustable. The holster is also very comfortable to sit/bend over while wearing. Due to the flex point in the middle of the holster, it does immediately feel more comfortable to wear than the Sidecar - The Agis adjusts to the curve of my body, rather than my body adjusting to the curve of the Sidecar. That makes a HUGE difference off the bat.
Another point of comparison between the Agis and the Sidecar is how high the magazine rides;
As you can see, the magazine sits slightly lower in the Agis than in the Sidecar. Except, the Agis is holding the OEM 21- extended to 27-round magazine, and the Sidecar is holding the OEM 17- extended to 23-round magazine;
The reason the Agis is able to hold a larger magazine lower than the Sidecar is because T1C allows you to specify in your order whether your spare mag is extended (options for +2, +4, and +6 extensions), and they then mold the spare mag carrier so that the extended mag sits no higher above your belt line than a stock magazine would. Pretty neat.
Another trick they've done to make larger spare magazines more concealable is to mold a small bump behind the belt clip on the magazine carrier;
This acts in a similar manner to the "claw" that has become common-place on AIWB setups; it pushes against the belt and causes the end of the magazine to push in closer to your body.
These few tricks combined with the shorter grip length of the Compact grip module results in a package that completely disappears under a shirt that I'd wear on a daily basis;
And, even more impressive, remains concealed even under just an undershirt;
This is a Nike Pro workout shirt - If you're familiar with them, you know the material is basically thin spandex. It would generally be antithetical to trying to hide something under it (particular a still relatively large pistol with a magwell and extended spare magazine), and yet...
Consider me impressed. I will of course need to do more practice drawing and see how the holster holds up over time, but for now I can fairly confidently say - If you're in the market for an AIWB holster+mag carrier setup, T1C should be on your list of considerations. Probably towards the top of it, in fact