It is. I encountered it around Qt4 time. I really liked Qt4 backthen, but I was also open to using/trying other things. Like Lazarus and U++.

It offers a more compact i'd say approach to develop and it's quite straightforward.

I only used it for small GUI applications, but you can see what others been building https://www.ultimatepp.org/www$uppweb$apps$en-us.html