Do you have an Android tablet and enjoy groove boxes? Then check this app out.
Ok, so I have only played around with this a bit, but it is quite nice. The drum samples are from very recognizable drum machines, and are perfect for this type of pattern making. The swing on the tempo is nice. Also, you can have separate filter and envelope parameters per note. Think parameter locking.
Where does this fall short? Only 8 patterns. Also, no copy and paste. However, the sound is nice. Definitely worth the DL if you have an Android.
I have not tired the “social” aspect of this app yet, but it lets me access and edit public songs, so I would assume that a private collaboration would work just fine too.