Two weeks ago I took the airplane instrument written where I used the King Schools class. That said for the FAA instrument written only thirty percent of the test was similar to the King test bank where numbers, places, etc were changed but the questions were more or less similar. On the other hand seventy percent of the FAA test was totally different questions...clearly new. Notable is that King teaches knowledge in their videos with quizzes at the end of each video session to validate understanding of the material in the lecture.
I reviewed the whole FAA test prior to submission but did not change any of my answers though I was uncertain of two responses. In the end I got three wrong. The two I was uncertain of and one that clearly was scored incorrectly (e.g. bad question in the FAA test question bank). On this latter question the CFII's at my school agreed with my assessment on the bad question. Overall I decided that the King video material paid off given I was able to answer the vast majority of the questions that made me think about the answers.
The take away should be that using a study method that teaches memorizing questions and answers, is unlikely to result in a good score on the current FAA test. On the other hand if you learn the knowledge and how to apply it to the new FAA questions you should do ok.
After the fact I spoke to a person who is familiar with the FAA test changes, where I was told that while the FAA threatened to change the written tests a year ago, the last update mid-year represented a much larger change. My sense is that the online ground schools are struggling to adapt. It might be the case that Sporty's and King with their larger focus on teaching more than memorization are now the goto solutions if a lecture works better as one's personal learning method.
For the starter of this thread, I started the King material while I was OCONUS. When I got back home to be honest I went through it again from the beginning and the second pass through really helped solidify the material, especially doing it just prior to taking the written. It took me 1.5 weeks on-and-off to review it the second time around. I think you will do well on the written with the King material.
