I really like my Mac, and I am thinking about developing Software for it some time in the future. What are the reasons why you're making Mac Software? Because you think Mac is so cool? Or is the market so interesting? I think many of us would like to know, right?
Well for me, as I said, it's the coolness of the Mac. I don't know anything about the market.
I like objective C as a language. I use mac's in my daily life. I like the flexibility of having a unixish operating system underneath. In short, it serves my needs and it helps me learn.
Users.
In some circles, Mac is the only option for some reason. You have whole companies without a single Windows machine.
In short:
The Objective-C language, Cocoa and the applications that Mac OS X provides developers with (not just Xcode and Interface Builder).
Slightly longer:
I love the Objective-C syntax and the countless number of functions that Cocoa provides. You can do so much stuff when writing apps for Mac OS X without even needing to write a single line of code. And you can do even more stuff when you write just really easy "glue code". And when you need to write "real" code to implement something that isn't already available in one of the frameworks, it doesn't feel so tiresome because in my opinion, writing Objective-C code is fun.
The market is interesting too, there are for example many areas where there just is software missing for the Mac so you can be the first one to make an application for a certain task which can be a great thing for a new company to jump in. The market is also frustrating though because I think nowadays people expect too much from Mac software, at least I do. Mac software not only has to be absolutely mindblowingly good in terms of the technical implementation and usability/intuitiveness, it also has to look beautiful or cool or whatever. This makes it really hard for one man software shops for example. You need to be a coder and a designer and that's said to be impossible although there are exceptions of course. Compare that to Linux for example where everyone is happy with the standard GUI tools that the GUI system of choice provides. Maybe it's not as bad as I think it is though, this is just my impression and I could be dead wrong.
I haven't done much Mac programming for about three years now but every time I develop an app in Java, C#, Ruby, C or whatever else I'm using, I catch myself dreaming about writing the app in Objective-C with Xcode instead. But then I also start thinking about the upsides of developing cross platform software instead of software that will only run on Mac OS X. I use Windows, Mac OS X, Linux and some lesser known operating systems and being able to use the apps that I write on every one of these platforms instead of just on the Mac is too nice to give up. That's why I mainly develop cross platform software these days although I do like developing for Mac OS X better.
Simple - because it's the OS I use. If I primarily used Windows, I'd probably be learning C#/.NET instead of ObjC/Cocoa.
Also, I would say Mac software has a better reputation than Windows software ("free Windows software" could be described as a pseudonym for "spyware"). There's a really good community around OS X software (sites like TUAW, iusethis.com etc etc), which I guess is because OS X has become quite recently, at the same time as all the blogging/social-media stuff has taken of ("good timing" more or less).
I attended a talk by Wil Shipley of Delicious Monster fame. His argument for developing on the Mac was quite simple:
These seemed to me to be quite compelling reasons, couple this with a less crowded market place.
This was in the days before iPhone, you have a much broader customer base these days.
In addition the 'enforced' MVC for developing Mac and iPhone App make porting between platforms very easy, see the example of Tweetie for the iPhone and now Mac.
I program for Mac OS X because it's the environment I use, and I decided that a good way to ensure the quality of the environment I use was to have a hand in constructing that environment. It helps that there are good communities of Mac users, admins and developers so that understanding the environment, what's hot or not and so on is both easy and quick. That community feeling gives me a chance to both learn from others and show off a bit, and I enjoy both of those things.
I actually moved to OS X from NeXTSTEP, and the reason I was on NeXT was exactly the same - it was what I used. The computing lab at Uni was NeXT-based, it was a good UNIX platform which was easy to use and to grok and I realised that if I was developing for this then I'd be contributing to the quality of my own user experience, and there'd probably be a job in it once I'd graduated (there was) ;-).
Like some of the other posters I also like the Objective-C language, but it's not a deal-clincher for me. I've written (and still do write) tools in C and Python, and have previously maintained WebObjects Java code. There's nothing wrong with any of these things.
I've been a mac user since 1984 and an apple user for even longer... nonetheless, I am still always inspired by how many amazing resources are available to developers right out of the box... (sometimes it takes a few years for those resources to get properly documented, but they are there and they are amazing.) examples: coreAudio, coreGraphics, coreVideo, FireWireSDK, etc etc etc...
I am not an evangelist and I am not paid by apple, just my $0.02
|K<
The Mac market is growing at an incredible rate. It's awesome to have your market grow without any work on our part ;)