I have had an M3 both ways (With and without EDC). Skipping EDC was a no-brainer for me on my latest M3 (ordered this one). If you run coilovers it's a button that becomes useless and you have to code it out. I was not impressed with the EDC suspension settings (I rarely went out of the middle mode). In the end coilovers are the best option considering you can tune the ride quality and height.
'04 E46 M3 - Jet Black - Sold
'08 E90 M3 - Alpine White - Sold
'13 E92 M3 - Silverstone II - Sold
'13 E92 M3 - Alpine White - Ohlins TTX, Fall-Line Suspension Arms/Bushings, AP Racing BBK, OE GTS Aero, Cobra Seats, Akrapovic GT4, GMG 4-point, BBS E88