I personally feel that SPD's are far superior. I ran toe clips for several years because I thought it was insane to "clip in" to your pedals. I have found it much easier to get my feet out of SPD's than toe clips and straps. To be able to make the most of toe clips, I needed to reach down and really tighten the strap every time I put my feet in them.
I have never had SPD failure. I never want to change the position of my foot from the ball to instep. If the pedal is in the instep of your foot, you don't get the extra power from your calf muscles.