I've a few things to add.
It was said somewhere in here that Galaxy and SV weren't closely tied together. Actually they were exceedingly so. For instance if you employed Galaxy with one of your synths then all of the patch names would show up in a popup menu within SV for your selection. This was very useful.
Performer was out before Vision, but MidiMac the precursor to Vision was out first. There was also a really neat app out back then called Midi Paint--this would be a great app to track down for the Garden.
Because StudioVison was the first "DAW" not counting things like the Firelight, or the Synclaver, it by definition was (at least at one point in time) the best.
One of the reasons that SV is so tight is that Opcode put a lot of effort into that area. Once you became aware of the differences of loose timing and tight timing you understand its importance. Opcode had on the Mac one of the tightest sequencers around. I don't remember the specifics, but the disparity was pretty big.
The Atari sequencers Cubase and eMagics were really tight on the Atari. When they moved to the Mac it loosened up a bit. I don't know if they ever got that back up to spec. But this is the main reason that the Atari was so loved by the techno crowd.
Vision did have some really neat uses of patterns though, and you could trigger them with a midi event. This meant in a live situation you could control not only your music gear, but lights too. It was pretty wonderful stuff. It looks like Gary mention this feature.
Blaming Gibson for Opcode's demise is only part of the story. You really have to know about how Gibson was able to buy Opcode. Even then Opcode probably would have survived the Gibson affair if Guitar center didn't go to war with Gibson. All of that happening at the same time is what took out Opcode. It's really sad. But two of the main driving forces for Opcode, Dave O, and David W, are now developing PT. So really if you think about it that way Opcode did take over PT.
Addressing the number of windows. It's a little bit difficult today to remember that people were still using computer with displays well under a 1,024 pixels wide. Some folks were still sequencing with 512 pixels of width. To even be able to get that much information out to the user it had to be done with a number of windows. The consolidation technology didn't become viable until just recently. Think of it this way DP didn't do it until DP8!