|The MacBook Air from Apple.com|
For starters, switching to Mac has is an entire post in itself but I'll keep it short with this: If you are used to (and rely on Microsoft Office) in a business environment, be aware MS Office for Mac is not an exact replicate. If you are a fan of Outlook for Windows, I warn you: Outlook for Mac is not nearly as robust as its Windows counter part. I have enjoyed using Mac Mail but it definitely doesn't handle a Microsoft Exchange server (most large companies use Exchange for e-mail) as well as Outlook, but it works well enough. Apple computers also ship with a lot of built-in, free software such a Preview (a great PDF program) and iPhoto (photo library and editor).
I have owned 2 Apple laptops, a 15" PowerBook (2005) and a 15" MacBook Pro (2010) and have been extremely happy with their longevity and the operating system (OSX, instead of Windows XP, Vista or 7).
When comparing the MacBook Air and the MacBook Pro, the main deciding factor is functionality. If you are looking for a computer to surf the web and check email, the Air is for you. It is extremely light weight, fast (flash hard drive), and a slick machine. Some major drawbacks about the Air are: No CD/DVD drive (i.e. no watching movies on disc or burning discs) and no on board network adapter (no plugging into a network cable at the office). Now, both of these short comings can be overcome with USB accessories, but it is worth noting. If you don't need a CD/DVD drive or a hard wired connection to the network (WiFi only) then these aren't deal breakers for you. The Air's flash hard drive is smaller, so keep that in mind if you are planning on saving lots of photos on your computer.
Now for the MacBook Pro... this machine comes with Firewire and Thunderbolt ports in addition to the USB, mainly for accessories as well as the CD/DVD drive. The Pro also comes with a better processor and larger (but slower) hard drive, of course you can always splurge for the solid state drive for better performance.
These two machine are also quite close in cost, so the features of one may be considered a wash for just $200, that call is up to you.
Well, it is past my bed time and I'm sure this could use a good proof-reading, but I'm wrapping up a server upgrade and going to bed. Best of luck, feel free to post specific questions, I'll try to answer them the best I can.