In contrast, the C language is fairly simple, except for a few twisty passages (pointer declaration syntax, anyone?). The standard library does leave something to be desired, but that's not that big of a deal given all the third party libraries out there.

It would be interesting to compare the same program written in straight C vs C++ vs Cello, both for developer experience issues (clarity, simplicity, etc.) and performance. I'll have to have a look at http://libcello.org/learn/benchmarks but this does really seem like something I'd like to use on a personal project someday.