When you have a DL4, the idea of having a delay pedal that does one kind of effect seems just silly.  If you want to use delay, you want this pedal.  It has the standard digital and (modeled) analog delays, but also has unique delays like reverse, ping-pong, delayed swell, rotary horn, etc, plus the loop sampler, which is its most famous feature.  Now let me say this . . . if you are after a loop station first and foremost, don't get this--look into one of Boss's stations; but the fact that a loop sampler is included among a long list of other great functions is a great selling point.  I play through an multi-effects unit that includes most of the delay options in this pedal, but I use this primarily since its usability is so great.