A small user report here.
I needed to quickly get a PCB made for testing something at the hospital lab. I downloaded DipTrace and within 3 work days I had added a 80pin Samtec QSE connector and a 96pin DIN 41612 connector to the library, done the schematic (~400 pins), routed the 200x80mm 4 layer board by hand, created the Gerbers and sent of to production.
I had to refer to the DipTrace manual / google search about 3-4 times during the process. The DipTrace UI is just really intuitive. I've used Mentor BoardStation and Zuken CR-5000 before, which are industrial grade packages, so I'm fairly au fait with the PCB design process.
In the meantime - Eagle, which I have been experimenting with for a couple of weeks, requires me to look things up for nearly every operation. I believe Eagle is more powerful than DipTrace, but the Eagle UI is just obtuse and many of the translations don't conform to any of the vocabulary used in the PCB industry (again, I'm looking at this from Mentor / Zuken). Eagle is hard to use, because it's poorly designed and dripping with legacy.
The Eagle autorouter is better than the Diptrace one, but the only reason I use the autorouter in Eagle is because the manual routing UI is just awful (can't move traces whilst maintaining 90, 45deg angles, etc). By contrast the manual routing in DipTrace is pretty good. Not as good as CR-5000 with real DRC and push-aside routing, but much better than Eagle.
I'm seriously considering buying DipTrace license instead of Eagle, especially as Eagle require the Auto-router module to get online DRC during manual routing. I don't want to pay for the autorouter which I'll never use anyway.