I use an Android, so I can't comment specifically, but if the iPhone BeerSmith app functions anything like the Android version then it's well worth the investment, though I am not sure if you need to own it on PC/Mac to get the full functionality from the app. Brewer's Friend is nice, though you have to pay for the service and the app. I think there are some free apps that provide essentially the same functionality as BeerSmith, though I wouldn't know what they are since it's been about 5 years since I owned an iPhone.