LMMS is music creation software similar to programs such as GarageBand for OSX and FL Studio for Windows. Those programs are designed to streamline the process of making music with a computer in order to get new users into music composition as quickly and painlessly as possible.
I mean, you can't argue with the price, right?
One possible issue with LMMS might not be the app itself, but the audio drivers in your Linux Distro. I'm still trying to figure out which Linux is best suited for my old Mac Pro -- if you've any advice on that please leave me a comment over on my WordPress blog.