A good PC runs the same. I develop software and rarely ever mess with my machines. They just work and work well. I have never had my PC crash. Ever. Considering the software I develop, they should have with everyone telling me how fragile they think they are. The main diff between a Mac and a PC is that the Mac is tuned for itself. The OS is designed specifically for the hardware it runs on, while the PC is generic and the OS folks (read: Microsoft) can't tune to a spcific machine. A good machine will run forever. Macs are great machines, they just don't have much of a corporate penetration so guys like me don't write software for them. That is changing. Computers are getting more agnostic everyday. The web is pushing that concept.
We're going to go look at the Mac tomorrow. If they have what she wants in stock, she'll come home with one. Microsoft Office for the Mac as well.
As for software, remember that as a Unix-based OS, OSX can also run quite a bit of software ported over from the Linux and Unix world. If you're halfway decent at reading compiler error messages and writing C, you can probably port some stuff that hasn't been officially ported, too. I have.