REAPER (Rapid Environment for Audio Production, Engineering, and Recording) is a digital audio workstation created by Cockos. It is distributed with an uncrippled evaluation license with a nag screen explaining the license cost. It is currently available for Microsoft Windows (XP/Vista/7/8) and Mac OS X (10.4-10.10). Linux is not currently supported, but the program can be successfully run using Wine/Wine64. Version 4 of REAPER was released on August 3, 2011
I started using Reaper in 2011 because I was tired of Acid crashing all the time and it was a great decision. It simply rocks and it's easy to use. A REAL professional DAW for producers with very affordable price and weekly updates!