I am an semi pro photographer shoot 2-4 times a week. I have both the quadra and the ranger RX speed. I use the quadra for location and studio shoots primarily as either my rim light or my key light. It is excellent very reliable. Love that it has the built in wireless receiver and easy menus though you have to spend 10 minutes to read the manual. Very light and so far durable. I take my gear everywhere. I am considering buying another quadra.
More and more I use this more than my ranger RX speed. The only thing it cannot do is overpower full sun. You will want the optional adapter to attach elinchrome modifiers.
There are cheaper lighting systems but this has been a good investment for me.