I've pondered your questions since I first laid hands on a Mac 20 years ago, and I have always made the decision to stay with Windows-based systems.
Primary things to consider:
1. money. Mac laptops are generally just over twice as much in cost to buy
2. type of portable system. Apple does not make netbooks, if you want a small system. I have just bought a netbook for use on holidays and I would have bought an Apple, but the cost of a good Windows system was £300, and the nearest MacBook was £800 and that was a 13" system, not a netbook.
3. type of desktop system. I have always paid around £1500 for each desktop system, the past four I have bought. Each time there has been much more power for that sum than the previous one had, but it provides the level of system I need. [my first PC in 1988 or so cost nearly £3000 and the specification was pathetic by today's standards]. Now, the iMac comes in at about that £1500 cost so it is a hot contender for a desktop system
4. what software you use. If you have 'legacy' [stuff you have used for years and need] software that you use on Windows, it may not work on a Mac. Apple users may say that their systems come supplied with most software that a normal user may want. It is certainly not true in my case. Macs these days can run Windows software, BUT only as something separate from the normal Apple stuff, so it kind of defeats what might make the system good for a Windows person. There is a greater and cheaper choice of software for Windows though Mac users might say it is not needed.
5. compatibility of data. Depends what you mean, but generally, file interchange between the two systems can be done. You just need to review what sort of stuff you want to be able to use on the Mac that you used on a PC.
For me, the things that count in my decision from the list above:
1. I don't want to spend twice as much for a badge and I'm not into 'cool'. I also know my way around a PC and one of the benefits of a Mac is that, for a novice user, they require little knowledge to set up.
2. I do wish they had a netbook, as I would have bought one if it were only half as much again in cost. The first netbook I ordered last week would not connect to my wireless broadband [hardware problem] so I sent it back. That would probably not have happened with a Mac. My new one, from a different manufacturer, will hopefully work when it arrives this week.
3.all-in-one- sytems like the iMac are brilliant in the showroom, because there is no 'desktop box' - it is all in the display. There are similar Windows systems from HP and Dell and others. However - if any one component goes bad, then you lose the whole shebang. On a system with discrete components, bits can easily be replaced. Jury is out on these systems, for me, but the iMac looks truly sexy.
4. I have such a mass of software that if I moved to a Mac then I'd have to retain a PC of some sort too, for the functionality. There is a version of Microsoft Office for Apple systems. Things like PhotoShop and Illustrator are available for [indeed originally came from] Apple. The cheap alternatives that I also use for those products are NOT available though, so Apple is more pricey once again.
5. data compatibility - I don't think I'd worry too much about that as most common formats will transfer.
What it comes down to for me is that, if I were a first time user, a light use user, a heavy user with limited need for broad functionality, a user with a wad of money to spend, and was not an IT professional, then I'd probably simply buy a Mac. If I wanted 'street cred', then I'd go for a Mac.
It is all very personal! When buying Windows systems I only ever buy from major manufacturers.
Jenniferpa ia a mac person and will fill in from the other angle, I'm sure.....
