Anyone who has heard me wax lyrical about programming will know my opinion of Visual Studio. If we ever get invaded by an alien race from beyond the stars I reckon that they will be here for our advanced technology and Visual Studio will be on their shopping list. It is the best development environment ever. And anyone can get a free version.
You might think that it is only used for Microsoft technology, but you'd be wrong. You can use it for all kinds of language and platforms because it has been built to support plug-ins. You can even use it to create Arduino solutions with the Visual Micro plugin.
The free IDE from Arduino is nice enough, but Visual Micro is wonderful. I used it extensively when I was creating the Wedding Lights. I had two Arduinos hooked up to my PC, master and slave, and I was able to deploy and debug programs in both of them at the same time using Visual Studio for everything.
There are a few issues that I've noticed. It supports a kind of debugging mode that I don't find terribly useful (I add lots of code instrumentation) but once you figure out how to turn it off it works fine. The system also doesn't have quite all the refactoring goodies that you have in "pure" Visual Studio, but Intellisense is present and correct, and that is really what you want, plus the lovely editor.
Visual Micro needs a "paid for" version of Visual Studio because the free Express versions of Visual Studio don't support plugins, but you can download and use Visual Micro for free. The way the licence works you can keep renewing it with out paying the company anything. But I've bought a licensed copy because I think people who produce systems as good as this deserve my money.
If you are serious about Arduino development you should get Visual Micro. Absolutely.