I also have the EDC and would order it again for the $$$. I must admit that I have been doing almost all of my winter driving in normal mode, but I do notice a difference when I put it in comfort. Also, in the summer I love to be able to hit the button and drive in sport, it really makes that car responsive.
IMO - It is a great option to have for our roads and you (or you wife) will not regret it, as it does make the M3 a great DD and track car. However, it is not a must and the M is still a great car without it.
2008 E93 M3 - SSII, 6MT, 19", EDC,...