Hey I just wanted to list some more good music programs.
-sunvox: available on ANY OS, I have run it on windows, mac, linux, and even my iphone and ipad... I am fairly certain that they have a windows mobile phone version as well. It is free unless you are running it on a cell phone or idevice(but cheap there also). The interface and control is nearly identical in all forms... but it utilizes the touch screen on the i devices, so thats a little different. The musical layout is similar to LSDJ, but I think it is much easier to navigate it, as it is not constricted to 4 buttons and an analog pad.
-Music studio: this is only for iOS, but I wanted to mention it because I think it has a great interface, and has some really awesome VSTs. This one will cost you 15$ to get the full version of, and you will have to lay down a few more bucks for the 8bit VST in it... but it's a pretty solid VST imo. This software was actually so good that the owners of FL studio commissioned them to do FL studio for iOS, and as a result FL studio on the iOS is nearly identical to music studio. But I haven't used the FL studio on iOS, so I'm not sure if it has any more or less features.. This program uses piano roll. It looks very similar to garage band. It also has some built in effects that are really nice. It has something similar to a kaoss pad built into it, and you can just move your finger on the touch screen and record it with your track.
