You don't need VS for TS. Eclipse and WebStorm support it pretty well. I've evaluated Visual Studio, Eclipse and WebStorm, and Eclipse and WebStorm are better for TypeScript development, at least if you're using Node.js.
In my experience, Typescript support in IntelliJ/Webstorm has always been sketchy --- so much that I find it quite unfair that they would mention this as a feature of the paying version.
I still use it, but I often get invalid highlighting, etc.. Then I update to the latest EAP because it's supposed to fix this particular issue... and then other appear. Hmm, annoying...
I tried the VS version as well, and there the highlighting and refactoring works very well... but the editor is waaaay slower so I always give up. Funny because it works fine when working with other languages such as C#.
I tried WebStorm and found their support for TS severly lacking, IIRC it was limited to automatic compilation and basic syntax detecting. Code understanding/static type analysis was basically non-existent, e.g. it wasn't checking if argument conforms the interface described in the method's definition - you had to compile the script to find that out.
