We've evaluated several obfuscation tools and ended up purchasing CliSecure by SecureTeam. Their tool implements advanced obfuscation techniques such as control flow obfuscation & cross assembly obfuscation, however their real competitive edge is their code protection solution. After protecting your assemblies all method bodies appears empty, I've been told that the code is handed to the JIT compiler on a per method basis just when needed. This was the perfect solution for us since we didn't have to go through additional QA cycle once protecting our app due to inconsistencies that are normally introduced when using an obfuscator. Last but not least their support is superb. We got immediate response for any question asked and were satisfied with the quality on feedback we've got.