Lots of very correct things said there...except for this: "The more you use the “clean” code methodology, the less a compiler is able to see what you're doing.

Lots of very correct things said there...except for this: "The more you use the “clean” code methodology, the less a compiler is able to see what you're doing. Everything is in separate translation units, behind virtual function calls, etc. No matter how smart the compiler is, there’s very little it can do with that kind of code." I suppose even that is true, but JIT compilation regularly walks right around those problems. Yes, your code is written to say virtual this, or override that...but the JIT don't care. Is it looking at a monomorphic call site? Or even if it's not, is it ok to think of it as monomorphic right now? Great -- inline away. All that being said...I once got into a readability tiff over the use of a Java enum in a particularly performance sensitive chunk of code. I went with ints so I could be very, very explicit about exactly what I wanted, and the rather large performance gain...and lost. Yay! Your mileage may vary, and your measurements may vary.