Hi, I switched to Macs in 2008 and love it.
Macs can run Windows AND Mac programs while WIndows can only run Windows programs.
All Macs come with Boot Camp pre-installed that walks you through the process of setting up a "Windows side" to your Macbook and you can also look up YouTube videos on how to do it fairly easily, too. Downside is that you have to shut down to go to the Windows side.
There are a few programs like Parallels and VMWare Fusion that you can buy, though, that make it super-easy and allow you to have the Windows side and the Mac side running simultaneously. We used VMWare Fusion when we switched in 2008, but really haven't needed it since that first week once we got the hang of Macs.
Either of these solutions should help you if you
need to run Otter (or any other Windows only program.)