I Have Many Times Used Both At The Same Shaving Session. A SE First Pass And Then A DE For 2nd And 3rd. Then Again Sometimes I Use Only A DE Or SE. They Both Have Advantages And Weak Points. I Vote "Can't Choose".
I've been on an SE binge lately, but today I picked up my R41 2011. Although my SEs are very efficient, none of them works as well as my R41, on my face.
I would be willing to try the new ATT SE1 because I think that the feather pro blades are a lot nicer than conventional SE blades.