I have seen several reviews on the Tac Com trigger, and all were negative. On the positive side, a few reviewers stated that they think that the issue may be that there is a lot of special technique, to learning how to get the trigger to work as advertised. Most reviewers only spent a few hours trying to get it to fire bursts, with negative results. They stated the learning curve may take weeks to months, until you can get the correct trigger control to be able to fire any type of controlled bursts.
I use a SlideFire stock, and from the very first use, I was able to control 3-4 round bursts easily, or could easily empty a full mag in three seconds. At the full price of $350, the SlideStock is a pricy toy, but not as pricy as the Tac Com trigger, which is still unproven.
Bob