Downside with Ableton is the Midi routing.
Philip Conway wrote:
Reaper, for one, is massively cheaper, is very stable and has extremely flexible audio routing capabilities. It isn't designed to be used live like Live is but if you just want a flexible host for plugins it could work well.
(apart from having to mime the first loop when using Ableton looper....which might be embarrassing)
Also Plogue Bidule is good if you want to run audio plugins
that take midi input and want it to just work without headaches.