I´ve had this pedal for 20 years, it has been standard component of my pedal board all this time. The pedal has 4 settings (level, feedback, time, mode) and it is simple to operate after you get familiar what each of them does. Maximum delay time is 800ms which is meager by todays standards, but for me it is more than enough. There is also option to infinite delay repeats with the “hold” option and pressing down the pedal, but I have never really used it because you can´t run normal delay at the same time. This is one of the minus things about DD-3, otherwise it is pretty much perfect for my needs.
Sounds and features:
It is digital delay, it does not colour the sound much, it just repeats the signal you put in faithfully. This can be a positive or negative thing, some people like the altered sound some analog delay-pedals give. Best way to run delay and all other time-based effects is to use the effects-loop on your amp, but I usually have this in front of my amp, because it is much more practical in live situations. Messing around with 4 different cables for just the effects is not what I want to do when performing, there is always some cable which shuts down. If you are fortunate enough to have people handling this stuff for you then it is a different thing of course. The pedal works nicely on front of amp too, but you have to be careful with the level settings or the effect gets too dominant.
Quality and reliability:
It is a Boss-pedal, it is made to last. Never had problems with it and I have played loads of gigs with it. This pedal has been road tested by guitar legends like Billy Duffy for decades.
My favorite DD-3 Digital Delay settings:
Level: 10 o´clock
Feedback: 10 o´clock
Delay time: 10 – 12 o´clock depending on song
Mode: 800 ms
This is my delay settings for lead guitar playing. I use delay-pedal front of amp.