Yeah, and add in that they can keep a beat, are never late, and are as consistent.
To add to what was written above (and I realize this is not a timely response), these Aps are pretty efficient at what they are intended to be used for, and I don't see anything like this in any other iPhone application. The learning curve to get going is about 15 minutes of playing around with it, and it took me about 2 weeks of futzing around to learn most of the tricks of the software.
I have all three, and Heartbreaker is the weakest of the group, although I think it has the best intros and endings.
One drawback to all three is that when slowed down to under @ 70 BPM, there is a loss of quality because they are being slowed down too much. One suggestion for a future genre is a slow tempo ID recorded as a slow BPM.
These Aps are great for quick and dirty drumtracks. You can program any section to be between 1 and 32 measures, and after a some experience, it becomes quick work to edit sections that are mid-track. This took awhile to figure out.
To me, the Ambiance section just rocks. It has such great separation, and gives the track a more professional feel.
To get the tracks to your PC, you go to a website, and I think a Wifi connection is required. You download the track, then import it into your recording software. After the first couple of times, this process is very simple.
Just thought I'd throw some comments out there. I love using these Aps, and I've created 8 complete4d songs so far using these drumtracks.
Rob