I normally dont buy in-app purchases but I did for this one and I couldnt be happier. I just finished PT school and have used this app countless times as a study tool and refresher while at clinic. The convenience is unmatched! It offers what an orthopedic textbook would but with video, references, and statistics (reliability, sensitivity, specificity, etc). When you consider textbooks costs hundreds of dollars it would be silly not to buy this app! I recommended it to my classmates. If that werent enough, when I had update issues, help was polite and prompt. Id give 6 stars if I could! Love this app!!