[Boost-users] [regex] Boost.Regex + ICU vs. standalone ICU

Hi there, Is there a document out there describing any substantial differences (in particular, w.r.t. semantics and correctness) between using Boost.Regex with ICU support baked in as opposed to ICU's built-in RegexMatcher/RegexPattern classes? I do realize, for example, that the former's API has a 'modern C++' style, whereas the latter is modeled on Java's -- but these differences seem to be mostly cosmetic. Is there anything else I should be aware of before deciding to use one or the other -- performance, functionality, ease-of-use, etc.? Thanks! PS: It doesn't look like xpressive has Unicode support yet, which is why I'm not considering it, but I'd love to know if this impression is false or soon-to-be false.