Think back to a wedding you've been to where you had a good time... do you remember the bride's dress? Do you remember the flowers? No. You remember if there was free flowing booze and if you had a good time. If you use an iPad and forgo the DJ you will be hosting your own wedding and it will likely end before you even have a chance to let loose and enjoy yourself. It will be hard to really be in the moment when you are watching the clock making sure to stay on schedule. This also goes for delegating the iPad controls to a family member or friend. Surely they will want to enjoy your wedding and be a part of it too, and not be a manager of the event instead. Do not make your friends and family be your staff - hire a professional.