This is great for making rap, R&B, club and hip-hop beats. It also does do things like rock and techno beats, and what have you, but it's more focused for the other stuff. One great thing is it's portable and you can run it on batteries so you can make beats anywhere you want. I've even used this flying on a plane.
Simple, easy to use. Unfortunately you cannot upload your own samples, and must use the built-in library, but it's not that bad. I enjoy the portability, and capacity to make beats with one piece of hardware and a pair of headphones while looking into the nearby city park(aka the forest). It does also have midi in/out/thru so you can utilize it to control other devices, as well! Totally worth the price.
Easy to use. Everything comes straight from the machine. Battery powered, so it great to use on the fly. I use this with my sp 404 for effects and more arrangements.
Only thing is that it eats up batteries, and it would be a spectacular machine if you can load in your own samples with a card or something. Plus I wish the pads were velocity sensitive But I guess that's what MPCs are for...
But still, I use it mainly for it's drums and some of the cool samples it has on it. I can get around the whole sample loading issue and combine it with my sp404.
Haven't used it as a controller yet... but i think you're better off with an actual usb midi pad. This is more of an external hardware