My info might be old, in my days, Allegro is the more common. Then Power PCB ( PADS). I myself use older version OrCad in my days, it was 10.2 at the time. I downloaded the latest OrCad, it is nothing like what I know and the files are not compatible.
I think learning is about the same, you learn one, you know what to expect from the other. Best is to choose the one that is the most common instead of worrying about which one is the best. It is more important to learn something that is in demand so you be able to find job easier in the future. I know PADS and OrCad, it was hands down OrCad is superior for RF design, not even close. But PADS is a lot more common and useful when looking for a job.