Yeah I started doing them recently. They are surprisingly pretty tough, and this coming from a chem major; I've had far better success with the old TBR passages.
Having said that, it seems pretty good practice - and best to get beat up now than on test day.
How are you guys approaching the passages? It's hard to mentally map the passages and the questions seem to involve a lot of novel reasoning based on the passages. Also, are you guys timing them?