I'm not qualified to comment as a "serious" user (as would be, say, someone doing mix/production for a living), but as a hobbyist it has been a joy and powerhouse to use and produce two little homebrew albums.
Another popular alternative for that kind of audiences is http://reaper.fm/ , from Cockos from Justin Frankel & co from Nullsoft who made WinAMP.
As a serious hobbyist, ardour is on the way to compete with pro tools. I decided to use ardour, musescore and ableton live for different purposes 3 years ago and I m happy. Reaper, logic pro, garage band etc don't give anything extra to Ardour after 6 months of trials I can say that.
Another popular alternative for that kind of audiences is http://reaper.fm/ , from Cockos from Justin Frankel & co from Nullsoft who made WinAMP.