Koushion MIDI Step Sequencer had some new ease of use features added today.

What's new:

• Scene manipulation controls: copy, move, and swap scenes!
• Gate rotary knob: adjust the length of each note from 0 to 200%
• Improved internal MIDI clock accuracy

Buy Koushion on iTunes: $9.99

There are surprisingly few user videos for this, I thought everyone loved step sequencers? Here is the original demo video.