Not quite sure about Qt. It indeed looks good on the outside. Code is pretty tidy, too. However, it has non-standard nature in its core. Licensing would definitely be a problem as well. In addition to that, adding another layer of C++ interface o top of a full-blown C++ framework would not make much sense. We should aim for a really thin layer on top of native GUIs that works out-of-the-box on a given platform. There should be a unified front-end, with platform back-ends - much like Data library and connectors are designed. You start with one back-end (probably Win32 first) and add others later.
Qt will add LGPL from 4.5 release,Qt is attractive,Qt has Qtcore,which is the base of QtGUI,QtCore has function which POCO has,if POCO does have GUI part, then I prefer POCO than Qt,if using both POCO and QtCore,they are competitive,I do want to only choose one, I think people who knows POCO would like it very much,like me.
so lack of GUI is the only pity of POCO.