Hi Thorsten,
Great post! We are in identical situations! I've tried ManagePro. I also first used IQ in 2009 - 2010. I liked it a lot but gave up on it. The power was unbelievable but I found it too cumbersome to navigate and manage.
Then I decided to give it a new try in 2015. This time around I was a little wiser about developing a strategy of how to structure it, and also found IQ had gone through enormous improvements. Now I love it and can't imagine finding anything I like as much. The biggest challenge is that it's so flexible and powerful you are no longer limited to the normal paradigm of adapting your workflow to the software you are using, with IQ you can endlessly adapt it to you.
That can become a bit addictive and time consuming! I've found myself rethinking a lot of things because of it.
BTW, if you create a new database you should see an option to load predefined grids with sample data, contacts etc. I do agree that eventually there should be some out of the box configs that are as simple as possible, but for now this is the ultimate power users product, no getting around that, and it takes time to learn. Even in my use I know I'm barely scratching the surface of what it's capable of.
Also, it is now possible to activate any number of column sets with the click of your mouse. Look in the properties pane. Once you create forms, you can load the column sets for the forums by right clicking and selecting "load column set". I'm not on my PC at the moment and telling you this from memory, I believe that's how you'll do it.