Now, with a plug-in system, you have loads of single windows floating around. Some people may like that, I clearly don't. "Lemme change that amp envelope here, add a little more compression and play around with the insert delay...". Now I got the synth open, my delay open, my compressor open and I'm trying to make those adjustment, still rearranging windows to be able to have an overview. Then I have to close all those GUIs again to be able to see my sequencer and the rest of my project.
With Reason, it's one hot key and I can see the rack, find my devices, make the adjustment, hit another hot key and I'm back at my sequencer. Yea, they didn't invent shortcuts, but the rack as the only space for devices, always, easy to spot (for me at least), is something I don't see many people talking about, but like I said, it's an essential part of keeping my workflow.