For my group management I use mobile application – GroupMan (https://play.google.com/store/apps/details?id=org.app.groupman).
Really nice, free and easy to use mobile APP with a lot of functions included (scheduling, storing of client information, pdf report generation, visual report generation, Facebook integration,…)
From my experience and also other trainers I’ve worked with, PTminder is much better suited for Personal Trainers as it is specifically PT focused. For example it includes recording of client assessments & measurements etc, whereas Mindbody does not. All round PTminder is a great product so would suggest trying that one out first. Amazing customer support as well. Hope this helps.