Past Years' CFAI Mock Exams vs. Schweser/Elan/Finquiz Exams

I have access to old CFAI mock exams as well as several other 3rd party practice exams, and I"m not sure which to use. Which are the most useful from a learning standpoint? Which have the best (comprehensive and well-written) solutions? Thanks!

You realize it’s against the rules to use old CFAI mocks exams?

With that being said Schweser has pretty thoroughly-written answers to the questions.