Tech 21's Sansamp Bass Driver DI is an awesome little box that offers both the flexibility of a direct input box, and the sound and control of a pedal. This is an analog piece of gear that has 1/4" connections for an input and two parallel outputs, and it also has an XLR output. It can be powered by a nine volt power supply and isn't rack mountable as it is controlled by your foot.
The make up of the Tech 21 Sansamp Bass Driver DI definitley makes it quite a flexible piece of gear. It can be used for live shows or in the studio, but I've only used it in the recording studio. As far as parameters go, it's got knobs for level, blend, treble, bass, drive, and presence, as well as a switch for phantom/ground. It then has a switch to engage or disengage the parameters. A manual shouldn't be necessary for most users.
Both as a traditional DI box and as a pedal, the Tech 21 Sansamp Bass Driver DI excels when it comes to sound quality. I love the sound of this when used as a simple DI box, but when paired with it's ability to be used as a pedal, the palette of sounds increases exponentially. You can definitely get a good sounding drive with this for when you might be looking for some more crunch and not just a clean DI signal. I've only used it with bass guitar - a Fender P Bass, and since it is designed for bass I don't think that I'd recommend using it for anything else. Although Tech 21 does make other similar devices for non-bass instruments.
The Tech 21 Sansamp Bass Driver DI is really the perfect combination of a DI box and an in depth bass pedal with a lot of control over your sound. I'd recommend that every bass player look into this, as it will definitely add a lot to both your live rig and in the studio. Studios should also consider having one of these around, as its the perfect one stop shop for recording bass guitar direct. All in all, deifnitely a reliable piece of gear with a great sound and a lot of flexibility.