The area51 repository continues to update, even as the official ports tree for FreeBSD sticks with KDE4. Since the KDE-FreeBSD team is also responsible for the official ports, that basically means that not everything has been shaken out yet, and that the team doesn't feel that it can provide a really good Frameworks5 / Plasma5 / Applications installation .. yet. I've been playing with ideas for a default desktop wallpaper (the upstream default gives me a headache; I'd really like to combine Flying Konqui by Timothée Giet with bubbles made from the BSD logo.
That said, Plasma5 and some Applications work very nicely on FreeBSD. They also produce plenty of .core files, so it's not all wonderful, but it's a usable desktop by all means (and of course, all your KDE4 and GNOME applications continue to work). I tried to install a Qt5-only (+Frameworks, of course) desktop and discovered a long-standing bug in gsettings, as well.
The KDevelop-KF5 beta is available as a port from area51 as well. There's an interesting potential bug there, too: it uses LLVM 3.5 libraries while the Mesa libraries use LLVM 3.6 in the software renderer. So if you have a machine without hardware GL, you can end up with two LLVM libraries runtime-linked into an application, which means crashy-time. This is the first time that upgrading my graphics card has fixed my IDE.