I can help out here, but Chris you have to go back and edit the OP to include StudioVision.
Okay arguably StudioVision was the very first program to integrate audio and midi at a high level. The previous apps were either a midi app, or a tape deck replacement. SV brought on the revolution. Would it have happened without SV? Sure, of course--but they were the first.
Lets talk about some of the cats that programed at Opcode. I'll start with Doug--he's most apropo to the current discussion because he was the architect of OMS. I was at Opcode while he was creating OMS--it was an exciting time, and working with Doug was heady.
Doug went on to Apple when Opcode died. Guess what he did there? The same thing.
Yup all of the Core Midi stuff was Doug doing OMS 2.0. This is why it rocks so hard. He took all his knowledge, and experience creating OMS, and applied it to Core Midi. There were probably some other folks that helped, but I don't know them so oh well.
Okay back to SV--Dave O. the captain of the Opcode ship, and the mind behind StudioVision went on to Digi after Opcode died. Guess what he's doing over there? Midi.
Yup so all that tasty midi that's been showing up in PT is thanks to Dave. SV was being developed at the same time as OMS was being developed. It was an exciting time at Opcode. At the same time this was going on David Z. was making Max a commercial product via Opcode. Yeah it was really fucking cool to be around all these super cats.
In answer to your opening question: The one you know. Really it seems like a goofy answer, but it's totally true. If you don't know one yet then see what your friends use, because then you'll have someone to help you when you get stuck--and you will get stuck. Although forums and YouTube have changes things so much.
For me StudioVision is what brought me to this forum. Many of the other apps have made it to OS X, and have improved significantly over the years. I'm totally blown away by the current version of DP. Yeah sure there are things that I'd like to see it do. Zooming for one--it would be great if you could zoom with the touch pad like browsers, iPads, and iPhones do. But for going back to OS9 I think it's about using something that was special in that time, and for me SV fits that option pretty well. There are things it does well that other apps still don't do. Ray's strip charts are still the best, and the replace event/selection tools will make your head spin with ideas (and glad you studied math).
If you get a chance on the E-mu Morpheus and Orbit there are demo songs that my buddy Jeremy and I did where I used a lot of my best SV continuous controller tricks. It was a lot of fun, and I'm grateful that E-mu was cool enough to let us do it.
