Like all Boss pedals, the Boss DC-3 is very user friendly and easy to use. The pedal has parameters for effect level, EQ, rate, and depth in the form of knobs. Everything is clearly labeled and extremely easy to follow. The manual is put together well, but it definitely isn't necessary unless you are looking for some really specific information.
The sound of the Boss DC-3 is definitely unique, although at the same time you will recognize some familiar sounds. I haven't really ever seen any pedals that are the same sounding as this one, so if you try out the pedal and like what it can do, this is pretty much your only choice to get a pedal just like this one. This being said, of course you can get other modulation effects like chorus and flanger which are similar, but not all in one pedal like this one. I use the pedal with a Fender Strat or a Gibson SG and a '76 Fender Twin Reverb for recording, and I can definitely get some pretty awesome sounds within this set up.
I've been using the Boss DC-3 for a few years on and off when I have access to it, as I do not own this pedal for myself. I definitely enjoy using the pedal simply because it is a unique blend of sounds and are hard to replicate elsewhere. The price of the pedal isn't isn't all that expensive, but since it is no longer being made and hasn't been made in a while, they can be hard to find and you will have to pay a bit more than for a normal pedal since it is rare. If you are interested in vintage Boss pedals or even just interested in messing around with some new pedals, the Boss DC-3 is a great pedal to look into.