Sean Coates has reposted an article that was originally published in php|architect magazine covering UTF-8 and proper Unicode encoding.
If I had to guess, I would estimate that I've spent somewhere in the range of 40 hours wrangling UTF-8 in the past 3 months, which is not only expensive for my employer, but also disheartening as a developer who's got real work to do. Admittedly, this number is inflated, due to the heavy development cycle we completed with the launch of our new site.
Sean goes on to talk about Unicode issues in general (partially supported in some places, too many points of failure) and some of his other experiences with "the UTF-8 monster" that have given him trouble over time.