Most people use the SP for beats. Most probably just use it for effects. Very few know its full capabilities. Find and RCA-1/8 cable and plug your guitars in, it becomes a mega-powerful effects pedal. If you know what you're doing you can get a normal guitar to sound like a bass...
The Roland SP404SX is absolutely a great addition to my rig and a value tool for sketching out new ideas. Its small enough to carry it inside your backpack and great campion to the iPad. The Roland SP404SX is a impactful piece of gear, a performance tool, that I have been using for most of groove production and creative exploration. I only had it for two months and I am already using it on my shows. I love the various effects so its an added feature to the unit that has endless possibilities. The effect selection is amazing period - I have found a unique use for many. As I mention before its battery operated, and the ability to have all your samples on a SD stick is a plus. The 404 is the machine of the future for those artist who want to explore sampling and the art of music production without the use of a computer.
This little sampler. Haha. It's full of surprises. A number of effects one can use is just crazy! I am yet to hear someone utilizing all of its features at once.