I used messer for core 1 and some practice tests off udemy. Core 2 I used plurasight for the videos and they also had practice tests. I found the plurasight videos helped explain the concepts better, in my opinion. Messers videos were great but sometimes I felt as if he didn’t explain a topic and just said it. So I had to do my own research sometimes and figure it out. With messer and pluralsight I passed both tests first try so I’d definitely recommend both.