ReSharper 4.5 provides significantly more robust code analysis, coding assistance, navigation, refactoring, code cleanup, and unit testing support compared to the base Visual Studio 2008 IDE. It offers over 750 code inspections and 550 quick fixes to resolve errors, 35 solution-wide refactorings compared to just 7 in Visual Studio, and integrates support for multiple unit testing frameworks like NUnit, MbUnit, and xUnit.net.