I have dually utilized Schweser and official CFAI material for the past two levels and have consistently found that Schweser does a better job of imitating what the actual exam will look like, with the exception of the actual exam being somewhat easier than a mock - which is my main gripe with Schweser.
Shweser, in my opinion, over-prepares you for what potential complications may arise (driven by Schweser’s hugely diverse bank of questions) which takes away the focus of a broad fundamental understanding of each section, which has hurt me in the past.
My guess is that, come exam day, the test is 3/4’s the diffuclty of the average of all the Schweser mocks (v.1-6) and, style-wise, the questions are almost identical to Schweser mocks as opposed to official CFAI mocks.