This is a pretty good list of obfuscators from Visual Studio Marketplace
Obfuscators
- ArmDot
- Crypto Obfuscator
- Demeanor for .NET
- DeployLX CodeVeil
- Dotfuscator .NET Obfuscator
- Semantic Designs: C# Source Code Obfuscator
- Smartassembly
- Spices.Net
- Xenocode Postbuild 2006
- .NET Reactor
I have not observed any performance issues when obfuscating my code. If your just sending text basted stack traces you might have a problem translating the method names.