I helped a guy install those once. They made the mirrors better, but not nearly as good as a set of the FZ1 mirrors. For my money, I'd go the FZ1 mirror route every time.
I'm using the spacers to move the stock mirrors out. I also added some tiny blindspot mirrors to the corners of my stock mirrors. This is the best setup for me, functionally and aesthetically. As a bonus, I mounted my auxiliary lighting to the mirror extenders. Others like the FZ1 mirrors, YMMV.