I am not certain how Notion Music does Mac and Windows versions of NOTION, and it is possible that there is a special software development platform that makes it possible to develop one set of source code with some platform-specific modifications, which is the way RealBASIC works, but perhaps not . . .
Regardless, the reality for software development in the Apple universe is that a significant amount of code is the same for Mac OS X applications and iOS applications, and the common code is increasing rather than decreasing, at least in some respects, so from my perspective focusing on iOS application development is stellar, since a good bit of the code developed for the iPhone, iPod touch, and iPad will apply directly to Mac OS X applications, although in this instance I think the specific iOS target device is the iPad, which is my focus, as well, since there is too little display space on the iPhone and iPod touch to do much of anything elaborate . . .
On the Mac, Notion 3 is stable, and it is working very nicely for me, so my general perspective is that focusing on iPad software development is great, since it has a vastly strong focus on the Apple universe . . .
I also think that this is good for the Windows flavors of everything, since no matter how Notion Music does it, there is a software development system or process that works nicely for doing both Mac and Windows versions of NOTION . . .
For older folks, such as myself, using a keyboard and mouse is very ingrained, and it is the user-interface I prefer, but for younger folks I think that everything is different, which is one of the reasons that the iPad is such an important form factor . . .
I am very skilled at touch typing, and I am able to compose and type a post like this at approximately 70 words per minute with nearly perfect grammar and spelling, which is fantastic, but if you watch youngsters working the keypad of a cellphone what you discover is that they can do pretty much the same thing, albeit with a somewhat cryptic language, which is an important bit of information when one gazes into the future toward the goal of determining how people will use computing devices . . .
Another fact is that the iPad will become faster and more powerful over the next few years, and what might be a bit much for an iPad to handle in terms of computing today will be easy for an iPad to handle in a few years . . .
The iPad is the "go to" form factor and computing platform at the dawn of the early-21st century, and focusing on developing applications for the iPad makes stellar sense for a many reasons . . .
And without wandering into a lot of software engineering stuff, the fact of the matter is that pretty much everything Notion Music is doing for the iPad will apply to the Mac, where I think a reasonable estimate is somewhere in the range of 75 percent or higher, and it probably is higher if everything is designed and structured correctly . . .
For reference, I have been a registered Apple Developer Connection (ADC) member for quite a while (Mac OS and iOS), so there is a lot of stuff about which I know but cannot say, since there are NDAs and so forth, but going on readily available Apple approved public information, I think it should be obvious that there are not so many differences in Mac OS X and iOS applications, at least with respect to the iPad and Mac desktop and notebook computers . . .
Yet another fact is that the iPad is a tablet computing device, and I have been studying and researching tablet computers for decades, which gives me some insights in the grand scheme of everything that most folks do not have . . .
And one of these insights is that the rules for user-interface activities are very different in an application that is designed for tablet computing, since in the tablet computing universe the primary input device is the finger, since the user-interface metaphor is "pen and paper", where the "pen" is a finger and the "paper" is the touch screen . . .
So, what happens is that the user-interface work moves from (a) the user doing most of the work via a keyboard and mouse to (b) the software doing most of the work and then packaging it so that the user can do everything essentially with a finger, which is excellent for a virtual festival of reasons, where one of the most important reasons is that it pretty much puts an end to what I call "lazy software engineering", where software engineers make an effort to move as much of the work to the user as possible . . .
"Lazy software engineering" is not so difficult to do for a desktop or notebook computing device that has a keyboard and mouse, but when the primary user input device is a finger, the software engineers and user-interface designers have no option but to do a lot more of the work, which is promoted to an even higher level by the reality that multilevel fly-out menus, hot keys, shortcuts, and all that stuff simply does not exist for a touch tablet when the user-interface is designed intelligently and thoughtfully . . .
For reference, I started doing Windows software development with the first version of Windows, and I continue to do it, although for the most part I switched to the Mac about a decade ago, and one of the realities from my perspective is that Bill Gates is a remarkably hyperactive fellow who needs to have constant geek-level feedback from computing devices, which for a while in the Windows universe mapped to having to deal with a virtual festival of frivolous and annoying messages when doing just about anything, with some of the messages having no purpose other than inquire whether you wanted to subscribe to MSN . . .
At some point, even the slow folks start to suspect that having to click on an "OK" button every five minutes in response to a virtual festival of silly pop-up messages is indisputable evidence of a mental deficiency, but so what . . .
So what! Bill did a good job, and the world moves onward and upward . . .
Summarizing, my perspective is that focusing on the iPad is stellar, and Notion 3 is working very nicely for me, which makes one of the most important rules of software engineering useful to observe:
If it is not broken, then do not fix it! And while I cannot explain all the reasons for my perspective, I think it should be obvious that the combination of an iPad and a Mac desktop or notebook computer has
vast potential for moving music composition and production to a new and quite amazing level, where an excellent thought exercise is to ponder the way things might work sometime in the future when you can do everything with your finger, with the idea being to focus not on the specific technical stuff that needs to happen behind the scenes (which is what software engineers, architects, user-interface designers, and so forth do) but instead to focus on being able to do stuff in an Utopian way, where stuff just happens without requiring you to know precisely how it works, for sure . . .
For sure!