I have a Macbook Air. It's a year old. I loved it when I first got it, but elements of it got irritating, and I bought a Pro about 8 months in. That's much faster with a better keyboard and generally better to write on (the air is fast until you've got a lot of files on it, and then even the biggest SSD struggles).
I'm now using my desktop again. It's windows and I do miss OS when I use it, but when writing professionally it's just easier to have everything compatible and formatted correctly. Lack of a CD drive can be an issue although you can buy a USB controlled one - it's quite slow!
Mac stores will help you move files, but they won't provide software, just recommend it. So you'll need to buy Microsoft Office for Mac, and then they'll move over your documents, for example. Software wise, there is a lot of Windows software that doesn't work great on Macs, so you'll probably have to find alternatives. There is a Mac store on the Air that has some good apps, but they can be more expensive than the windows alternatives.
Writing wise, I found that most of the time things I created in pages and saved as word docs would mess up, but Office could send things to Windows users with them looking the same. The issue was getting files sent to me. Some would open perfectly, others would be badly formatted or missing parts. It depends on what the Windows users settings are.
Oh, and if you work with big companies/editors, you might find that they use Office 2013 which isn't supported on Macs. It's supposed to be coming, but nobody knows for sure when it will, or if it will.
I do love my Macs, and I wouldn't swap them for the world. I take at least one everywhere with me. I'm just aware that they lose their 'sparkle' quite quickly, and they are very expensive.