I own a DE and several straights. I would say that I use my DE when I'm rushed for time in the morning. I use my straights on days when I am less rushed and I also use them before going out in the evening.

As far as which gives a better shave? I find that the shaves I get from DE's and straights are equally comfortable but the straight does shave a bit closer. A straight shave takes longer because of the stropping before and after and making sure the blade is dry... however, the extra closeness more than justifies the extra time.