Exceptions create walls to reusing code
Joe Beda has "some theories as to why C++ hasn't developed the same set of libraries that other environments such as Perl, Python, Java, C#, etc. have. [...]
Code written to deal with exceptions doesn't interop well with code that turns exceptions off. [...] In any case, the result is that these are walls to reusing code."
Watch out for exception confusion, PHP 5!