DAZ Studio 3 is easy to use, but at the beginning it has a strange GUI that makes it difficult to understand. It is solved if you just dedicate 15 minutes to see the tutorial videos and have a look at the manual.

The same happens with Hexagon, the modeler, which I use for everything, from modeling to UVs. It has a strange GUI, but I learned everything in 4 days just reading the manual and following it.

Poser is not easy at all also. Unless you familiarize with it, the GUI is as strange as in DAZ Studio. Just remember when you started to understand how it works and remember, you surely found it strange.

These are applications that are not a web browser or a text editor, their interface is not standard and are not intuitive. But the learning curve for DS is faster than Poser.