After using Audacity for about a year I
have heard about Ableton.
Apart from that audacity is free and versitile
it takes some time editing a song while
selecting, cutting, correcting, copying
, shifting and pasting samples.
Is working with Ableton much faster?
Editing audio takes time. There’s no way round that (other than to pay someone else to do it 
)
In previous employment I used Audacity, Adobe Audition, Cakewalk Sonar and Protools on a daily basis. For most tasks, using Audacity was quickest. For little editing jobs, I could often do the entire task and export the finished in less time than it took for the other programs to launch. Audacity became my tool of choice for small editing jobs simply because it is so fast (once you know your way round the interface and a few shortcuts).
Whatever program you use for audio editing, you will become quicker as you become more familiar with the user interface.
Choosing the right tool for the job depends on what the job is, and your ability to use the tool efficiently. I would not use Audacity for “loop based” music composition, because there are much better programs for that type of work (such as Ableton), and I would not use Audacity for projects that require MIDI control, but for small to medium size editing tasks, Audacity would be my first choice every time (which is how I first became involved with the support and development of Audacity).
it takes some time editing a song while
selecting, cutting, correcting, copying
, shifting and pasting samples.
Like Steve says, audio (and video) editing takes time. The human interaction usually takes more time than the computer processing.
It can easily take 1/2 a day to a full day (or more) to edit a 1-hour program, depending on what you’re doing… It takes an hour just to listen-through the program before editing and another hour to listen-through after editing. Add some time in-between for editing and checking your edits (sometimes more than once) and the hours can add-up.
There may be cases where you’ve already listened-through the program and you just want to make some small change/edit and in that case you may not need to listen-through the whole program after editing, but most of the time you’ll be spending more than “real time” for the editing.
Computer-processing time is usually more related to file reading/writing than the actual processing, so your choice of software makes little difference. The exception would be programs like MP3DirectCut that directly work on (smaller) compressed files and WaveRepair that only writes changes to the file without necessarily re-writing the whole file (unless you are editing/processing the whole file).