Any time you talk about a reverb/delay pedal, you'll inevitably be drawn into the 'analog' versus 'digital' debate. Critics of digital delay argue that it's too sterile, lacks warmth and *cough* digital, while analog critics would argue that analog can get muddy and lack definition. Personally, I think each serves a purpose. With that in mind, the Boss RV-3 Reverb/Delay is very much a digital effect.
If you're looking for a pedal that can do Reverb and Delay, and the Line 6 DL-4 is out of the question, then the Boss RV-3 is well worth a look. It offers 11 modes to play with, four reverb modes, three delay modes (with up to 2000ms of delay) and four simultaneous reverb and delay effects (eg. delay and reverb on at the same time). The only minor issue with the simultaneous modes are that delay time is restricted to a maximum of 1000ms.
The delay modes are every bit as good as those found in the Boss DD-3, offering slap back style delay all the way through to extended delay trippiness. The delay tone does not really attempt to emulate an analog delay tone, which I think is a good thing. It is crisp and clear.
Reverb wise, there is also a crispness to the tone that can at times border on too bright. Rolling off on the highs using the tone knob can bring things back nicely however.
The reverb/delay combination modes can be great for creating psychedelic sound scapes, and would be sought after by anyone looking to take an ambient guitar trip. Try these settings for a spaced out guitar solo that'll cut through the mix; Balance 2, Tone 2, R. Time 5, Mode 7.
Like most delay based pedals, the Boss RV-3 has a relatively high power draw, so don't rely on 9v batteries, or this will eat them up.
The Boss RV-3 has been used by a wide range of guitarists, particularly metal and 'nu-metal' guitarist, such as Munky from Korn, Wes Borland from Black Light Burns (formally of Limp Bizkit), Meegs Rascon from Coal Chamber as well as experimentalists like Jonny Greenwood from Radiohead and Mike Einziger from Incubus.
