Ableton Live user, I quickly encounter the problem of controlling the software.
Do live mouse with a keyboard master, is not clear, although the keyboard includes a number of controllers.
Banks should provide more control and it quickly become unmanageable inconsistent with the live show.
I've decided to purchase the APC20, after hesitating between the controller Novation Launchpad equivalent of a tariff, and his big sister (APC40) outside my means.
Regular users last week, I can tell you that with the APC20, Live up to its name and it will take to the games
Perhaps a future David G. or Stephane P ...
For me it Marc D. there I see the smiles that link.

Most
Directly functional (that would be a shame for a dedicated controller)
Intuitive, no need to read the manual fro
Backlit pads, very sweet. Comfort is good too.
Removable side protection. in case ... when this cowardly.
Akai finish. What else.

Least
Controller has dedicated Ableton Live
Obligation to install Ableton Live Lite (for pilot)
Not compatible with Ableton Live versions below 8.

Conclusion:
On value for money interesting
Users of Ableton Live! In your banks, you would not be disappointed.