I'm resurfacing my deck with Trex Transcend. Some of the boards are the square edge variety so they have a clean look on one side, but on the other side I need/want the groove for the spacer. In another case, I needed to rip two adjacent boards so as to fit in the available space. There too I needed/wanted to put the groove so that I could use spacers.
I read other reviews about this product and concluded that this was better than the Trex branded router bit.
The first time I used it, I thought something was wrong because I didn't feel any drag as I was making the cut. I assumed I had completely missed the board and was getting ready to reset the depth. Then I saw that I had a nice clean groove in my board.
You do have to experiment a bit when setting the depth. Initially I assumed that I would want the groove in the middle of the board, equidistant from both edges. It turns out, this groove is a little slimmer than the groove on the grooved boards, so you should test fit a scrap before cutting a grove on your installed piece.
I would agree with other reviews that claim this bit is better than the Trex bit. Also, this bit is very sharp and seems to be very durable. It has certainly been easy to put a nice clean groove in my decking.