Now that Ardour is going to get AU support it only lacks multitrack beatslicer and I'm ready to change.
This is the feature why many people choose protools or nowadays samplitude. It's quite essential for many studios who do lots of drum recording and pop music. In the past I worked with zero x beatslicer and nowadays with samplitude 10's tool. But I'm ready to throw them away and go for Ardour if it only would have this tool.
I think Samplitude's new tool is excellent example how it should work. I'm just quite fed up of samplitude's stability and latency issues..