I am currently studying for the SIFT and using multiple training books, test prep, etc. The concept of this app is great, but there are way too many errors for me to feel comfortable trusting this app. Grammatically it is a nightmare. The math questions are written in a way that makes me think that Google translate was used. The biggest issue, however, is the aviation knowledge portion. I am a helicopter pilot currently, and there are answers in this app that are incorrect. I’m afraid this app, in its current state, will lead people astray who are prepping for a test that could change their entire future. I don’t recommend.