It's not a particularly good one unless a static linking exception is included (dylibs on OS X are a pain for no serious benefit, it's not viable at all on Android or iOS).
(Edit: I can't seem to quote the LGPL section 4, so here is a link to it: https://www.gnu.org/licenses/lgpl.html#section4)
There is a massive reluctance in the QT community over this currently -- people want to distribute single-binary applications, and they are told to be careful about doing it.