IMO, Royal edition is well worth it. Mostly because they have videos explaining the answers to every question. At first, I did not pay much attention to them, but towards the end I went over every explanation especially for TFE and Key holes and it started clicking in my head where I should look for those minute differences. Tutorials are ok, but you can find that info on other SDN. My scores were 16's on the first 3 tests, then started getting 18's last few tests 22, 19 and 20.
On the actual DAT PAT got a 21.