ReSharper is the greatest extension for Visual Studio.
- Code Refactoring.
- Linting
- Code Coverage.
- Code Tracing.
- Disassembly and Inspection.
Cons
- ReSharper, because it does so much, can be quite a resource hog on slower developer machines.
- Some ReSharper tools, like test running, seem to jostle with .NET's tools rather than replace or complement them (even though ReSharper's tools are superior!).
- Tools like DotPeek could be better integrated with the Visual Studio IDE.
- ReSharper has saved time (and thus money!) by disassembling and creating PDB files for libraries that did not ship with them, enabling complex bugs with third-party software to be quickly diagnosed and resolved.
- ReSharper is considerably cheaper than a Visual Studio Enterprise subscription, so it is well worth the investment if Visual Studio Professional's tools are not enough and yet you cannot budget enough for Enterprise.
- ReSharper has saved future losses with its linter by highlighting potential issues at development/compile time before they make it to production.